October 31, 2026
- GLM 5.3 autonomously weaponized the Firefox patch gap across six releases shipped between September 17 and October 26, at roughly $1,000 in API fees per successful exploit, according to Epoch AI. Given only the target build, basic tooling and public information in an offline environment, the model identified disguised upstream security fixes, chained them with a previously unpublished flaw, and produced a webpage that read local files from any visiting Firefox user and sent them to an attacker server. Neither Z.ai nor the other API providers tested returned a refusal; Anthropic had earlier assessed GLM 5.3 as writing exploits at roughly the level of Mythos (The Decoder).
· AI & Offensive Automation
in Open-Weight Model Turns Firefox's Patch Gap Into Working Exploits
October 4, 2026
- CVE-2026-61500, an unauthenticated RCE in Rejetto HTTP File Server (CVSS 9.8), was discovered by Anthropic's Mythos and reported by Horizon3: HFS derives session keys from
Math.random(), a reversible PRNG, and a separate unauthenticated path leaks outputs from the same generator, so a Z3-based solver can recover the admin session key and reach code execution. Affects HFS 3.0.0–3.2.0, fixed in 3.2.1; per the write-up, VulnCheck Canary began observing exploitation on 1 October (@DailyDarkWeb).
· Vulnerabilities & Exploits
in AI on Both Ends of the Exploit Chain
July 8, 2026
- CISA is reportedly using Anthropic's "Mythos" model to scan U.S. government code repositories for flaws that could aid foreign spies or criminals, work led by its Attack Surface Evaluation team. SecurityWeek, Yle/NCSC-FI
· Policy & Industry
in Synacktiv Drops a Kerberos Reflection Bypass That Hands Attackers SYSTEM
July 4, 2026
- "Bad Epoll" (CVE-2026-46242) gives local users root on Linux 6.4+ and newer Android. The kernel flaw sits in the same stretch of code where Anthropic's Mythos model recently found a different bug; the PoC reached 99% reliability and may be triggerable from the Chrome renderer sandbox. A fix is out. The Hacker News
· Vulnerabilities & Exploits
in Silent Active Directory Recon and a Near-Perfect Linux Root Exploit Lead the Offensive Beat
June 24, 2026
- OpenAI expanded its Daybreak initiative with the full GPT-5.5-Cyber model, an updated Codex Security plugin, and a 25+ partner network, claiming it outperforms Anthropic's Mythos on a cybersecurity benchmark and shifting focus from finding to auto-patching vulnerabilities. The Decoder.
· AI & Model Security
in Two Netlogon Flaws Hit Domain Controllers as FortiBleed Lands in Finland
June 23, 2026
- Anthropic's feud with the US government escalates — MIT Technology Review unpacks the dispute around Anthropic's Mythos model and what to watch as government pressure on AI capabilities grows. MIT Tech Review
· Industry & Policy
in Five Eyes Warns Frontier AI Will Reshape Offensive Cyber Ops as a New Entra ID Conditional Access Bypass Surfaces