CPython: [CVE-2026-87910] tarfile hardlink fallback ignores custom extraction filter rejection via None
CPython CVE-2026-87910: tarfile's hardlink fallback ignores custom extraction filters that reject entries via None, rated MEDIUM severity.
Petr Viktorin disclosed CVE-2026-87910 on the CPython security-announce list, rated MEDIUM severity. The flaw is in the tarfile module: when a custom extraction filter rejects an entry by returning None, the hardlink fallback path ignores the rejection. The posted excerpt did not include affected versions or patch details.
ChatGPT Flaw Let a Planted Prompt Send a Victim's Gmail Data to Another Account
Check Point showed a planted prompt could make ChatGPT silently exfiltrate Gmail data via a hidden cross-container channel; OpenAI took the service offline.
Check Point Research demonstrated that a single planted instruction in a ChatGPT conversation could make the model silently exfiltrate Gmail data, chat history, and files to an attacker's account while replying normally to the user. The covert channel abused read/write properties on files in an internal JFrog Artifactory instance shared by ChatGPT code-execution containers across accounts, turning package metadata into shared storage. Injection vectors included pasted prompts, shared conversations, and custom GPT builder instructions; default connected-app permissions allowed Gmail reads without user approval. OpenAI confirmed the internal service was taken offline after disclosure; this is Check Point's second reported ChatGPT covert channel after a DNS-based one fixed in February.
ThreatsDay: 296K IoT Botnet, 100+ Water Systems Targeted, SharePoint RCE Chain + 27 New Stories
Weekly ThreatsDay bulletin details a ShinyHunters-style social engineering hit on ReliaQuest, the 296,000-device Dysphoria IoT botnet, and several new malware families.
ReliaQuest confirmed a social engineering attack on August 22, 2026, in which an attacker used a fake SSO page and MFA push approval to gain brief view-only access to an identity dashboard, with tactics matching ShinyHunters, which has since listed the firm on its leak portal. The Shadowserver Foundation reported the Dysphoria botnet has compromised nearly 296,000 IoT devices for DDoS attacks and recently added residential proxy capability. Cisco Talos documented JWR, an operator-driven phishing-as-a-service framework linked to The Outsider that harvests credentials, identity documents, and 2FA codes over an encrypted WebSocket. New malware coverage includes the Octagon Android fraud bot ($1,400/month), the C2Looper Rust backdoor delivered via ClickFix, and the Aeternum loader that moved C2 to the Polygon blockchain.
New Cryptographic Context Injection Attack Could Let Web Pages Steal Grok Chat Data
Adversa AI demonstrated 'Cryptographic Context Injection' making xAI's Grok leak chat history and session data to attacker-controlled servers via encrypted web payloads.
Adversa AI disclosed a technique where a web page carries an encrypted JSON object (PBKDF2 and AES-256-GCM) that Grok's code-execution runtime decrypts, letting attacker instructions bypass content classifiers and reach the model's context. The decrypted instructions direct Grok to embed the user's name, approximate location, subscription tier and ongoing conversation into a URL it fetches, exfiltrating the data without confirmation. Testing targeted grok.com running Grok 4.5 Fast on August 19, 2026, with a reported 40% success rate over 20 attempts since June; no CVE, patch, or in-the-wild exploitation is reported. A related demonstration reproduced Gemini 3 Flash system instructions via a fabricated Python traceback, while GPT-5 failed to parse the payload and Claude Sonnet 4.5 flagged it as prompt injection.
FrostyGoop’s Zoom-In: A Closer Look into the Malware Artifacts, Behaviors and Network Communications
Unit 42 dissects FrostyGoop OT malware, which sent Modbus TCP commands to disrupt heating for 600+ apartment buildings in Ukraine.
Palo Alto Unit 42 analyzed new FrostyGoop/BUSTLEBERM samples, the ninth known ICS-centric malware, first used against a Ukrainian municipal energy company by sending Modbus TCP commands to ENCO control devices. The attack caused a two-day heating outage affecting over 600 apartment buildings during sub-zero temperatures. The Go-compiled malware accepts Modbus register operations and timing parameters via command-line arguments or a JSON configuration file, uses an obscure open-source Modbus library, and checks the Windows BeingDebugged flag to evade debuggers. Unit 42 telemetry recorded over 1 million Modbus TCP devices exposed to the internet between September and October 2024.
Cardinal RAT Sins Again, Targets Israeli Fin
Unit 42 documents updated Cardinal RAT attacks against Israeli FinTech firms, using BMP steganography, MD5-hash obfuscation, and process injection to hinder analysis and detection.
Unit 42 tracked a series of attacks using an updated Cardinal RAT (version 1.7.2) targeting the Israeli financial technology sector. The .NET loader hides a second-stage DLL inside an embedded BMP image decrypted with a single-byte XOR key, and the payload renames functions, methods, and variables to MD5 hashes for obfuscation. The malware installs a startup-folder LNK file and injects its final payload into RegSvcs.exe or RegAsm.exe, communicating with affiliatecollective[.]club over port 443. A possible relationship with the EVILNUM JavaScript malware used against similar organizations was also noted.
Fake CVE-2023
A fake PoC for WinRAR RCE CVE-2023-40477 posted on GitHub actually deploys VenomRAT through a multi-step infection chain targeting researchers.
Four days after Zero Day Initiative publicly disclosed the WinRAR RCE vulnerability CVE-2023-40477 on August 17, 2023, an actor using the alias whalersplonk published a fake proof-of-concept on GitHub. The Python script actually repurposed public PoC code for GeoServer SQL injection CVE-2023-25157 and triggered an infection chain ending in VenomRAT. The README and an accompanying video lured users into running the script; the video drew over 100 plays. Unit 42 assesses the actor was opportunistic, targeting other miscreants adopting new vulnerabilities rather than researchers specifically.