{"data":{"id":"fe1ef13a-c588-46cf-9920-f309d96ced89","title":"GHSA-953h-535j-jg2v: agent-router: MCP session resume does not verify the embedded anti-hijacking subject; default Helm seed makes session IDs forgeable","summary":"The Envoy AI Gateway MCP proxy's session-resume path never checks the subject (JWT `sub` claim) embedded in the client-facing session ID, so any client holding a session ID can resume another user's session and invoke backend methods such as `tools/call` and `resources/read`. The official Helm chart aggravates this by defaulting the session encryption seed to the publicly known `\"default-insecure-seed\"`, which would let an attacker forge session IDs.","solution":"N/A -- no mitigation discussed in source.","labels":["security"],"sourceUrl":"https://github.com/advisories/GHSA-953h-535j-jg2v","publishedAt":"2026-10-19T16:53:26.000Z","cveId":null,"cweIds":null,"cvssScore":null,"cvssSeverity":"medium","severity":"medium","attackType":["other"],"issueType":"vulnerability","affectedPackages":["github.com/envoyproxy/ai-gateway@>= 0.4.0-rc1, < 1.2.0-rc1 (fixed: 1.2.0-rc1)"],"affectedPackageNames":["github.com/envoyproxy/ai-gateway"],"affectedPackageRefs":["go:github.com/envoyproxy/ai-gateway"],"affectedVendors":[],"affectedVendorsRaw":["Envoy AI Gateway","MCP (Model Context Protocol)"],"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":["GHSA-953h-535j-jg2v"],"affectedPackagesSource":null,"affectedPackagesCheckedAt":null,"patchAvailable":true,"disclosureDate":"2026-10-19T16:53:26.000Z","capecIds":null,"crossRefCount":0,"attackSophistication":"moderate","impactType":["confidentiality","integrity"],"aiComponentTargeted":"agent","llmSpecific":false,"classifierConfidence":0.85,"researchCategory":null,"atlasIds":null}}