{"data":{"id":"c516ffdb-e994-4107-9813-d8bd15a358d7","title":"Endor Labs’ AI SAST Finds Zero Day Memory-Amplification DoS in Anthropic’s buffa library | Endor Labs","summary":"Endor Labs reports that its AI SAST engine flagged an unbounded-allocation flow in decode_unknown_field in buffa/src/encoding.rs, the protobuf decoder in Anthropic's Rust library buffa. A length prefix from untrusted wire data sizes a Vec<u8> allocation with no bound beyond fitting in a usize, and the researchers extended it to a memory-amplification denial of service of about 22x, tracked as GHSA-f9qc-qg88-7pq5 / CVE-2026-55407 (CVSS 4.0 6.3). Any message decoded from untrusted input with preserve_unknown_fields=true, the default, was affected.","solution":"Fixed in buffa and connectrpc 0.8.0 (affected versions are below 0.8.0).","labels":["security"],"sourceUrl":"https://www.endorlabs.com/learn/endor-labs-ai-sast-finds-zero-day-cve-2026-55407-buffa","publishedAt":"2026-11-11T02:21:08.000Z","cveId":null,"cweIds":null,"cvssScore":null,"cvssSeverity":null,"severity":"medium","attackType":["denial_of_service"],"issueType":"news","affectedPackages":null,"affectedPackageNames":null,"affectedPackageRefs":null,"affectedVendors":["Anthropic"],"affectedVendorsRaw":["Anthropic","buffa","connectrpc","Endor Labs AI SAST","Claude"],"classifierModel":"claude-haiku-5-5","classifierPromptVersion":"v4","summaryPromptVersion":"v2","headline":null,"headlinePromptVersion":null,"cvssVector":null,"attackVector":null,"attackComplexity":null,"privilegesRequired":null,"userInteraction":null,"exploitMaturity":null,"epssScore":null,"epssCheckedAt":null,"kevDateAdded":null,"advisoryAliases":null,"affectedPackagesSource":null,"affectedPackagesCheckedAt":null,"patchAvailable":null,"disclosureDate":"2026-11-11T02:21:08.000Z","fixReleasedAt":null,"daysToFix":null,"fixCheckedAt":null,"capecIds":null,"crossRefCount":0,"attackSophistication":"moderate","impactType":["availability"],"aiComponentTargeted":"api","llmSpecific":false,"classifierConfidence":0.8,"researchCategory":null,"atlasIds":null}}