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The skb that wasn't freed - the Fragnesia primitive via Open vSwitch

Doyensec details CVE-2026-90049 in Open vSwitch, enabling deterministic Linux kernel local privilege escalation on default major distribution installs.

Doyensec reports that the Open vSwitch datapath strips the SKBFL_SHARED_FRAG flag from packets it is still forwarding, allowing an in-place decrypt to write attacker-chosen bytes into root-owned page cache — a Dirty COW-class primitive that re-opens the Fragnesia bug family. The issues are tracked as CVE-2026-90049, CVE-2026-89487, and CVE-2026-80977, and were reported to the kernel security team with fixes coordinated alongside OVS maintainers. A deterministic local privilege escalation works on default installs of Arch, Fedora, Debian, Amazon Linux, and RHEL where unprivileged user namespaces and openvswitch auto-loading are enabled; the fix landed in mainline and shipped in stable on 09/04/2026. The write technique builds on the earlier Fragnesia and Dirty Frag bugs, including CVE-2026-43284 and CVE-2026-43500.

Phishing Campaign Sends Millions of Emails Using Invisible Unicode to Evade Filters

Microsoft warns of a high-volume phishing campaign using invisible Unicode characters to split keywords like 'funding' and evade filters, peaking at 2.37 million daily messages.

Microsoft's Security Research team documented a high-volume phishing operation inserting deprecated Unicode Tags characters (U+E0000-U+E007F) inside financial keywords such as 'funding' so literal-string and regex email filters stop matching them. The campaign ran on a weekly cadence with 1-2.37 million weekday messages between February and May 15, 2026, peaking on February 26, 2026. It used hundreds of disposable finance-themed sender domains and relayed mail through ActiveCampaign's click-tracking infrastructure (acemlnd[.]com, activehosted[.]com), lending legitimate platform reputation. Microsoft ties the activity to an AI-assisted SBA loan phishing campaign that Fortra's FIRE team disclosed in September 2025.

The Hacker News · 12d agoPhishing & fraud in the wild1

An AI-Assisted Cyber Attack: Inside a Unit 42 Investigation

Unit 42 investigated a ransom attack in which frontier AI agents autonomously breached an enterprise network, compressing weeks of tradecraft into under 10 hours.

Unit 42 incident responders documented an intrusion where a single human operator directed frontier AI agents to breach an enterprise network autonomously as part of a ransom attack. The agents executed more than 50 MITRE ATT&CK techniques in under 10 hours, work that would normally require roughly two weeks of human red-team effort. They breached a public-facing web service, mapped internal microservices, scraped hard-coded secrets from code repositories, harvested root credentials from the secrets manager, and hijacked CI/CD builds to exfiltrate cloud access keys. The attacker also used stolen cloud keys to repurpose the victim's AI endpoints as post-compromise infrastructure and left behind an 80-page AI-generated security audit documenting dozens of exploited findings.

Palo Alto Unit 42 · 15d agoThreat actor in the wild

GhostCode Phishing Kit Bypasses Microsoft 365 MFA to Hijack Accounts in 78 Seconds

eSentire identified GhostCode, a phishing kit abusing Microsoft 365 OAuth device-code sign-in to steal tokens and take over accounts in seconds.

eSentire analysts identified GhostCode in late August, a phishing kit that uses business contact-form messages and an NDA pretext to deliver a password-protected HTML attachment leading victims to a Microsoft device-code sign-in. Victims authenticate on legitimate Microsoft pages, letting the kit obtain a Primary Refresh Token in 32 seconds and register three devices in 78 seconds, with residential proxies matching the victim's location. The kit hides its redirect with encrypted addresses, junk data, and scanner-filtering challenges, and uses GHOSTnet-linked infrastructure during device enrolment. eSentire recommends blocking device-code authentication via Conditional Access, invalidating tokens, and reviewing newly enrolled devices.

Cyber Security News · 19h agoPhishing & fraud in the wild 8 sources5

China-linked Fire Ant Hides Inside Trusted Infrastructure

China-linked Fire Ant backdoored Cisco IOS XR routers, injected TACACS libraries to steal credentials, and rewrote logs across infrastructure targets.

Sygnia reports the China-linked espionage group Fire Ant compromised Cisco IOS XR routers with purpose-built malware, injected a library into the TACACS authentication daemon to capture live credential material, and manipulated syslog so only messages containing 'Health' were logged. The group used GRE tunnel interfaces with no commit history, rewrote wtmp/utmp/btmp login records, and deployed dormant deep backdoors on Linux systems — one disguised as a SentinelOne agent, another activated by raw network traffic carrying a magic string. Code-level overlap with UNC3886 tooling suggests evolution of that China-nexus cluster's TACACS credential-collection techniques, and Fire Ant used compromised infrastructure to scan SSH, RDP and web ports toward high-value networks.

Security Affairs · 16d agoThreat actor in the wild1

Threat Brief: 3CXDesktopApp Supply Chain Attack (Updated)

Trojanized 3CXDesktopApp installers for Windows and macOS loaded RC4-encrypted shellcode delivering a backdoor to hundreds of thousands of 3CX users.

Threat actors compromised the 3CXDesktopApp build process, adding malicious libraries (ffmpeg.dll, d3dcompiler_47.dll) to installers downloaded from the developer's website. The Windows MSI loader decrypts embedded shellcode with RC4, sleeps for a random 1-4 weeks, then beacons to C2 hidden in icon files on GitHub. Unit 42 fingerprinted 247,277 IPs across 199 countries using 3CX applications and blocked shellcode execution at 127 Cortex XDR customers between March 9-30, 2023.

Palo Alto Unit 42 · Aug 17, 2026Threat actor in the wild1

Operation RapidRust: APT36 Deploys RUSTYSHADE, RUSTYMOVE, PSNATCH, and BASHNATCH

Zscaler details Operation RapidRust: APT36 deploys four new tools including RUSTYSHADE, a Rust backdoor using private GitHub repos for encrypted C2.

Zscaler ThreatLabz documents Operation RapidRust, a campaign by Pakistan-aligned APT36 deploying four new tools: RUSTYSHADE, a 64-bit Rust Windows backdoor that uses attacker-controlled private GitHub repositories with a hardcoded PAT and AES-256-GCM-encrypted messages for C2; RUSTYMOVE; PSNATCH, a PowerShell file stealer that scans Office documents, archives, media, and databases modified in the last 120 days and exfiltrates up to 5 GB per run to per-machine GitHub repositories; and BASHNATCH. The backdoor was dropped via PowerShell from attacker-controlled Backblaze B2 storage and supports screenshots, webcam capture, file listing, downloads, and shell command execution.

Zscaler ThreatLabzupdated · 19m agofirst · 19h agoThreat actor in the wild 3 sources

Off Guard: Breaking LiteLLM from authentication bypass to cloud compromise

Wiz found LiteLLM auth bypass (CVE-2026-59822) and post-auth RCE (CVE-2026-59821) chainable to cloud compromise; the bypass is in CISA KEV with in-the-wild exploitation.

Wiz scanned roughly 3,074 internet-facing LiteLLM deployments and found 9.6% accepted the default master key sk-1234 or required no authentication, making post-auth attacks effectively pre-auth. The MCP endpoint accepts any Bearer token and grants a valid session (CVE-2026-59822), confirmed exploited in the wild via honeypots and added to CISA's Known Exploited Vulnerabilities catalog. Custom code guardrails allow post-auth root-level RCE via exec(compile(...)) (CVE-2026-59821), while pass-through endpoints lack URL validation, enabling cloud credential theft in post-auth scenarios. All assigned vulnerabilities have been patched; the research was presented at DEF CON 34.

Wiz Blog · 7d agoExploit / PoC in the wildCVE-2026-59822CVE-2026-598211