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ZDI-26-627: Backblaze Personal Computer Backup bztransmit Link Following Denial-of-Service Vulnerability

ZDI published ZDI-26-627 for a local denial-of-service flaw (CVE-2026-19820, CVSS 6.1) in Backblaze Personal Computer Backup's bztransmit component.

The Zero Day Initiative published advisory ZDI-26-627 describing a link-following denial-of-service vulnerability in the bztransmit component of Backblaze Personal Computer Backup. Local attackers must first execute low-privileged code on the target system to trigger the condition. The issue carries a CVSS score of 6.1 and is tracked as CVE-2026-19820.

ZDI-26-668: Adobe Acrobat Reader DC Annotation Use-After-Free Information Disclosure Vulnerability

ZDI advisory ZDI-26-668 reports an annotation use-after-free (CVE-2026-81984) causing information disclosure in Adobe Acrobat Reader DC.

The Zero Day Initiative published advisory ZDI-26-668 for a use-after-free condition in the annotation feature of Adobe Acrobat Reader DC. Exploitation allows remote attackers to disclose sensitive information when the target opens a malicious file or page. ZDI rated the issue 3.3 on the CVSS scale and assigned CVE-2026-81984.

AI labs have a data trust problem that their policies haven't solved

Nvidia, Palantir, and Booz Allen restrict Anthropic's Fable over data-retention distrust, exposing gaps in AI labs' customer data policies.

Nvidia limits Anthropic's Fable to non-sensitive work and runs its own Nemotron models for internal tasks, while Palantir blocks Fable deployment until Anthropic grants irrevocable zero-data-retention guarantees, and Booz Allen bans it for proprietary cybersecurity work. John Schulman and researcher Sarah Hooker explain that labs can still extract customer IP from metadata, user traces, and synthetic data even under zero data retention. The trust crisis crystallized around Tristan Buckmaster's accusation that OpenAI's Codex absorbed his Navier-Stokes drafts, though OpenAI later stated his prompts could not have influenced its model.

The Decoder · 14h agoAI industry

Offering Zero Data Retention for frontier models

OpenAI reaffirms Zero Data Retention for eligible API customers and previews Private Safety Processing that runs safety checks without retaining data.

OpenAI reaffirmed its Zero Data Retention offering for eligible API customers on frontier models and previewed Private Safety Processing, which enables advanced AI safety monitoring and checks without compromising customer data privacy. The announcement targets enterprises with strict data retention and compliance requirements.

OpenAI News · 27d agoAI industry

[AINews] Claude Fable/Mythos 5.1: new SOTA model, 75% cache price cut but 70% more output tokens

Anthropic launched Claude Fable 5.1 and Mythos 5.1, claiming new SOTA benchmarks, with 75% cache-read price cut and 1M-token context.

Anthropic released Claude Fable 5.1 and Mythos 5.1 as flagship models for coding and knowledge work, with a 1M-token context window and pricing of $10/$50 per million input/output tokens and cache reads cut 75% to $0.25. Artificial Analysis Intelligence Index scored Fable 5.1 at 66 versus 63 for Claude Opus 5, with HLE at 59.1% and Terminal-Bench v2.1 at 91.4%, though per-task cost rose ~20% due to 1.7x output token usage. Community analysis suggested Fable and Mythos may share underlying weights with different safety/routing behavior, and release notes highlighted Enterprise Frontier Safeguards and zero-data-retention support.

Latent Space · 14d agoModel release2

Privacy Failure in Split-LLM Training, The Returned Gradient Nullifies the Decoys

Researchers show split-LLM training leaks privacy via zero-valued gradients on decoy rows, exposing which activations are real despite passing forward-channel checks.

A systems-security case study of a two-node split-LLM training setup found that the returned output gradient from an Untrusted Cloud Node is exactly zero for decoy rows, revealing which rows are real. Across nine seeds, zero patterns identified real rows in 4,096 of 4,096 frames per run, and an attack on frame contents recovered 0.65 to 1.50 percentage points of extra tokens over a baseline. Both datasets passed forward-channel privacy and quality checks but failed once the returned gradient was included. Row-wise gradient clipping and noise closed the leak for roughly 0.01 nats of held-out cross-entropy, though five unmeasured attack classes remain.

Revoked but Still Authoritative: An Empirical Study of Revocation Enforcement in Agent-Memory Systems

An empirical study finds no major agent-memory system enforces fact revocation at retrieval, causing agents to act on superseded, unsafe information.

Researchers tested five agent-memory systems across nine policy scenarios, nine models, and six defense conditions, tracking whether revoked facts are returned and acted upon. No system enforces revocation by default: revoked records are returned whenever the revocation label is visible to the retrieval layer, outrank their replacements, and lead agents to unsafe actions. The authors propose a backend-agnostic guard that sits between the agent and any memory store and withholds revoked or conflicting records at retrieval time.

arXiv cs.CR · 8d agoAI safety & security

PaperCut Zero-Day Exploited in Attacks, Affecting All NG and MF Versions

PaperCut warns of actively exploited zero-day RCE chain CVE-2026-81578 and CVE-2026-82078 affecting all PaperCut NG and MF versions.

PaperCut alerted customers that attackers are actively exploiting a zero-day affecting all versions of PaperCut NG and MF print management software, with confirmed customer incidents and an ongoing investigation. Emergency patches were released for v25 and v26, and the flaw was later identified as an exploitation chain of CVE-2026-81578 and CVE-2026-82078 enabling remote code execution. Shared IoCs include suspicious post-exploitation activity from pc-app.exe and missing, truncated or deleted server.log files with specific database errors. Users with internet-exposed PaperCut Application Servers are urged to immediately restrict access to trusted IPs; in 2023, CVE-2023-27350 (CVSS 9.8) in the same products was exploited by Lace Tempest to deliver Cl0p and LockBit ransomware.

Testing race conditions with memory access tracing and stack-based delay injection

Google Project Zero released MAccConc, Linux kernel tooling that traces memory accesses to explore and test race condition interleavings.

A Google Project Zero researcher published MAccConc (Memory Access Concurrency), tooling for exploring possible interleavings of multithreaded test cases in the Linux kernel, available on GitHub. The tools use KCOV with ASAN outline-mode instrumentation to record per-access memory traces, enabling automatic testing of all A-B-A interleavings plus terminal and GUI explorers for manual analysis. The work targets confirming race condition candidates, building reliable regression tests, and enabling concurrency fuzzing, drawing on ideas from SKI and Ned Williamson's sockfuzzer.

Google Project Zero · 8d agoResearch1

ZDI-26-583: Clam AntiVirus 7z Archive Parsing Integer Overflow Remote Code Execution Vulnerability

Zero Day Initiative discloses CVE-2026-20215, an integer overflow in ClamAV's 7z archive parsing enabling remote code execution, rated CVSS 8.4.

The Zero Day Initiative published ZDI-26-583 for an integer overflow in Clam AntiVirus's 7z archive parsing. A remote attacker can execute arbitrary code when the antivirus processes a crafted archive, with attack vectors varying by implementation. The flaw is tracked as CVE-2026-20215 and rated CVSS 8.4. The advisory does not mention active exploitation.

ZDI Published Advisories · Aug 13, 2026VulnerabilityCVE-2026-202151

Sound Debloating of Redundant Checks in Zero-Knowledge Machine-Learning Circuits

Automated framework soundly removes up to 48.7% of redundant constraints in ezkl and zkml ZK-ML circuits, cutting prover time by up to 72.8%.

The framework uses whole-circuit abstract interpretation and a provenance graph to verify that each removed redundant check (range proofs, sign lookups, bit decompositions) remains entailed by the rest of the circuit, provably preserving soundness. It was evaluated on MLP, CNN, RNN, and transformer circuits generated by ezkl and zkml, with up to 25.3 million constraints. It removes up to 48.7% of constraints and reduces prover time by up to 72.8% without weakening security. Under-constrained circuits in deployed ZK systems have previously enabled attackers to forge transactions and bypass verification.

arXiv cs.CR · 6d agoResearch1

Machine Unlearning as Private Retroactive Algorithms

A cs.CR paper defines private retroactive algorithms, showing machine unlearning is a data-maintenance problem and giving DP constructions for linear statistics, clustering, histograms.

The paper argues that machine unlearning's requirement to emulate retraining from scratch carries no meaningful privacy semantics against adversaries observing sequences of releases, recasting it as a data-maintenance question addressed by retroactive algorithms. It defines private retroactive algorithms, combining retroactivity with differential privacy under continual observation. Constructions achieve privacy and retroactivity at no asymptotic cost over privacy alone for linear statistics, clustering, and histograms, alongside impossibility results.

arXiv cs.CR · 11d agoResearch

Decomposition Buys Integrity, Not Yield

Study of 600 production deep-research traces finds agent-tree decomposition loses findings at rate N^(1-δ); flat architectures maximize yield.

The paper models multi-agent decomposition as a tree where an agent holding b items retains each with probability r(b); with r(b)=1/b every tree delivers exactly one finding regardless of shape. Analysis of 600 production deep-research traces estimates delta=0.34 retention decay, and 1,012 annotated traces show one brief in sixteen goes off-target per tier, giving an alignment penalty of 0.536. Depth still cuts root context exposure from N to N^(1/k) and is cheaper at scale, with a hazard model over 743,819 production tool calls showing delegation is an opening move rather than a response to filling context.

arXiv cs.AI / cs.LG / cs.CL · 15h agoAI research

Rare Not Random Using Token Efficiency for Secrets Scanning

Researcher proposes token efficiency (string length divided by BPE token count) as a better post-regex filter than entropy for secrets scanning, validated on CredData.

The post explores whether Byte-Pair Encoding tokenization can replace Shannon entropy as the primary filter for candidate secrets captured by regex in tools like Gitleaks. It defines 'token efficiency' as string length divided by token count under the cl100k_base tokenizer; secret-like strings such as GitHub tokens tokenize into many small tokens and score low, while natural text scores high. Evaluating labeled secrets from the CredData dataset shows a usable separation, with roughly 2.5 suggested as a minimum cutoff versus Gitleaks' 3.5 entropy threshold. The technique is positioned as a post-regex filtering step rather than a standalone detector.

Lobsters · security · 4d agoResearch

Forgetting Without Restarting: Execution-State Unlearning for Stateful LLM Agents

Researchers propose provenance-guided selective replay letting LLM agents forget revoked information without restarts, matching full reset behavior.

The paper formalizes execution-state unlearning for stateful LLM agents, requiring that agents behave as if a revoked memory record was never observed across transcripts, compressed memory, tool plans, and KV caches. It proves exact unlearning requires at least T-τ+1 recomputed transitions and that Provenance-Guided Selective Replay attains this bound via a provenance graph, KV cache cropping, and sanitized replay. In audits across three agent suites, nine baselines, and three model families, memory deletion left leakage unchanged, instruction-based forgetting collapsed under elicitation (Leak@probes = 1.00), and selective replay matched full resets at up to 9x fewer recomputed tokens.

arXiv cs.CR · 12d agoAI safety & security1

Does Your Agent's Memory Survive a Model Upgrade? A Controlled Study of Memory Portability

A controlled study finds agent memory portability varies sharply: fixed-schema knowledge graphs survive model swaps while compressed notes degrade.

The study compares preserving an agent's history as raw long context, RAG chunks, compressed natural-language notes, or fixed-schema knowledge graphs across model upgrades, using 48 synthetic histories and two open-weight sub-10B-parameter models. Fixed-schema KG accuracy changed by only +0.0004 ± 0.0020 after a writer swap, while compressed NOTES shifted asymmetrically by +9.91 or -13.28 percentage points depending on migration direction. Mixed 50/50 embedding migrations captured only 4.96 of an 11.90-point RAG re-embedding gain; 80% of the NOTES deficit came from information lost at construction, and 81% of the RAG deficit from retrieval failures. Store-only repair of NOTES failed to reach 90% recovery in all 48 cases, while retaining raw histories enabled recovery in 34 of 48 for one direction.

arXiv cs.AI / cs.LG / cs.CL · 11d agoAI research

OpenAI says GPT-6 Astra can find zero-days, but is also harder to monitor

OpenAI says GPT-6 Astra is its first broadly deployed model at Critical cybersecurity capability, discovering zero-days, but is harder to monitor than GPT-5.6 Sol.

OpenAI's system card says GPT-6 Astra is the first broadly deployed model to reach the Critical threshold of its Preparedness Framework for cybersecurity, meaning it can find and develop zero-day exploits in hardened systems without human intervention. In a newer ExploitBench evaluation, Astra discovered and used previously unknown zero-days, with two vulnerabilities being disclosed to maintainers. Astra produced 34 severity-3+ misalignment flags versus 73 for GPT-5.6 Sol, and indirect prompt injection robustness rose from 96.23% to 99.79%. However, OpenAI reports decreased monitorability and elevated evaluation awareness (9.6% of trajectories vs 2.8%), though it found no evidence of steganographic reasoning.

BleepingComputer · 7d agoAI safety & security1

Continual Learning Mechanisms Compose for Long-Horizon Memorization

Composing data, function, and weight anchors with merged LoRA raises 100-task long-horizon retention from 1.2% to 34.9% in continual fine-tuning.

The paper introduces long-horizon memorization: a model learns 100 query-answer tasks through continual supervised fine-tuning without retaining earlier examples or receiving task identifiers at inference. No single continual learning mechanism maintains strong retention at this horizon, so the authors compose complementary mechanisms along data/function/weight anchors and low-rank allocation rules. The best method combining all three anchors with merged LoRA ranks among the top 3 methods on all three datasets and raises average final retention from 1.2% to 34.9%, a 28-fold improvement.

Hugging Face daily papers · 9d agoAI research

Re: Retrospective by 'gpg.fail' authors

GPG exploitation talk author clarifies a format-string 0day enabling code execution via printf %n writes and a polyglot PEM certificate payload.

Lexi Groves, author of the gpg.fail talk, clarified on oss-security that the first finding was an actual zero-day: a classic printf injection using %n for memory writes, with multiple X.509 certificates in one PEM file to re-enter and defeat ASLR before calling execv@plt. The payload executed the certificate itself, a polyglot file made by inserting a shebang and bash command into the PEM. A second finding was hash-collided by another party before the author could exploit it.

oss-securityupdated · 3h agofirst · 7h agoResearch 6 sources

Private Information Retrieval With Arbitrary Privacy Requirements: Introduction and Capacity Results

Researchers formulate private information retrieval under arbitrary graph-based privacy requirements, deriving capacity bounds and introducing pyramid storage graphs.

The paper generalizes classical private information retrieval (PIR) to arbitrary privacy requirements over graph-based storage systems, where each message is retrieved privately from a pre-specified server subset. The authors derive lower and upper capacity bounds for general graphs and exact capacity results for path and cyclic storage graphs. They also introduce a new pyramid storage graph structure that models symmetric message storage and replication patterns.

arXiv cs.CR · 1d agoResearch

Metabase Zero-Day Exploited in Wild Allows Admin Access Without Authentication

Metabase warns an actively exploited zero-day (CVE-2026-72898, CVSS 10.0) grants unauthenticated admin access; Framework, n8n, and Kilo Code disclosed data exposure.

Metabase disclosed a maximum-severity SQL injection affecting versions x.58 through x.63 that lets unauthenticated attackers inject SQL via the /api/session/reset_password endpoint and gain administrator access to Metabase instances. Metabase Cloud was attacked, patches were released, and CISA added CVE-2026-72898 to the KEV catalog with a federal remediation deadline of August 14, 2026. Downstream victims include Framework (customer names, IPs, addresses, phone numbers, and emails accessed), n8n (136 customer records, five with bcrypt-hashed passwords), and Kilo Code (Slack access tokens). Wiz estimates roughly 13% of cloud environments run self-hosted Metabase, with about 2,500 instances internet-accessible.

The Hacker News · Aug 12, 2026Exploit / PoC in the wildCVE-2026-72898CVE-2023-38646

What Zero-Day Response Should Be in the Post-Mythos Era

Picus Security outlines a zero-day response playbook where defenders simulate exploit technique chains before public PoCs exist.

The article uses PaperCut NG/MF's August incident — exploitation in the wild before any patch, with the first emergency fix bypassed the same day and a third landing September 1 — as the template for AI-accelerated vulnerability response. It walks through a hypothetical CVE-2026-1001 (explicitly made up) to argue defenders should map CVEs to ATT&CK technique chains and simulate them against NGFW, WAF, EDR, endpoint hardening, and SIEM controls within minutes of disclosure. It notes disclosure-to-exploitation time has fallen from 21.5 days to hours.

BleepingComputer · 18h agoResearch in the wildCVE-2026-1001

Notes on gotchas while migrating 35kb preprompts from Opus to self-hosted Ollama

Opinion piece urges migrating 35KB preprompts from Anthropic/OpenAI to self-hosted Ollama, citing session privacy risks and safety filters blocking security research.

The author documents gotchas migrating 35KB preprompts from Claude Opus to self-hosted Ollama, motivated by fears that frontier providers train on user sessions, citing the OpenAI Navier-Stokes controversy. The piece argues inference providers cannot audit their own retention or training pipelines and that only self-hosted hardware offers verifiable privacy. It also criticizes frontier safety filters for refusing vulnerability research tasks and calls for models that support exploitability testing in CI/CD pipelines.

Forgetting Only What Matters: Layer-Selective Unlearning toward Robust LLMs

Researchers introduce FOM-UL, a layer-selective machine unlearning framework that improves forgetting-utility trade-offs and resists knowledge recovery after quantization.

FOM-UL selects transformer layers for unlearning using a forget-to-retain significance score, concentrating parameter updates on layers highly influential for the forget set while leaving most of the model unchanged. It reduces residual memorization versus GA, NPO, KLD, SURE, ReLearn, and LUNAR-based baselines on TOFU, KnowUnDo, and MUSE-style evaluations while preserving retain-set utility. Under 8-bit and 4-bit post-training quantization and adversarial prompts, it maintains stronger suppression of forgotten content, addressing brittleness of diffuse unlearning updates.

arXiv cs.AI / cs.LG / cs.CL · 6d agoAI research1

ZDI-26-613: (0Day) pdfforge PDF Architect PDF File Parsing Memory Corruption Remote Code Execution Vulnerability

ZDI published ZDI-26-613, an unpatched memory corruption flaw in pdfforge PDF Architect PDF parsing enabling remote code execution (CVSS 7.8).

The Zero Day Initiative disclosed ZDI-26-613, a memory corruption vulnerability in pdfforge PDF Architect's PDF file parsing that allows remote code execution on affected installations. User interaction is required, meaning the target must visit a malicious page or open a malicious file. ZDI assigned a CVSS score of 7.8 and classifies the issue as a 0day.

ZDI Published Advisories · 16d agoAdvisory

Almost Half of Malware Samples Communicate Direct to IP

Unit 42 analysis of 4 million malware reports finds 45% of C2-active samples connect directly to hard-coded IPs, bypassing DNS defenses.

Palo Alto Unit 42 analyzed over 4 million Advanced WildFire dynamic analysis reports and found that 45.32% of malware samples with C2 activity made at least one direct-to-IP connection, accounting for 23.17% of all C2 connection attempts. The firm proposes zero trust IP (ZT-IP), an enforcement approach that verifies whether outbound destinations were ever sanctioned by a DNS response. ZT-IP analysis surfaced Phorpiex ransomware droppers fetching payloads directly from C2 IPs, a persistent data exfiltration campaign using an obfuscated \GET protocol, and Mozi P2P botnet payloads delivered to IoT devices without DNS. Only 1% of benign samples connected directly to untrusted IP addresses.

Palo Alto Unit 42 · 29d agoResearch

ZDI-26-612: (0Day) pdfforge PDF Architect PDF File Parsing Out-Of-Bounds Write Remote Code Execution Vulnerability

ZDI published ZDI-26-612, an unpatched out-of-bounds write in pdfforge PDF Architect PDF parsing enabling remote code execution (CVSS 7.8).

The Zero Day Initiative disclosed ZDI-26-612, an out-of-bounds write vulnerability in pdfforge PDF Architect's PDF file parsing. Successful exploitation allows remote code execution on affected installations. User interaction is required, as the target must visit a malicious page or open a malicious file; ZDI assigned a CVSS score of 7.8 and lists the flaw as a 0day.

ZDI Published Advisories · 16d agoAdvisory