{"id":"CVE-2025-64527","aliases":["BIT-envoy-2025-64527","GHSA-mp85-7mrq-r866"],"url":"https://o3.security/vulnerability/CVE-2025-64527","summary":"Envoy crashes when JWT authentication is configured with the remote JWKS fetching","details":"### Summary\nEnvoy crashes when JWT authentication is configured with the remote JWKS fetching, `allow_missing_or_failed` is enabled, multiple JWT tokens are present in the request headers and the JWKS fetch fails.\n\n### Details\nThis is caused by a re-entry bug in the `JwksFetcherImpl`. When the first token's JWKS fetch fails, `onJwksError()` callback triggers processing of the second token, which calls fetch() again on the same fetcher object.\n\nThe original callback's reset() then clears the second fetch's state (`receiver_ and request_`) which causes a crash when the async HTTP response arrives.\n\n### PoC\n* `allow_missing_or_failed` or `allow_missing` is enabled\n* The client send 2 Authorization headers\n* the remote JWKS fetching failed\n* There will be crash\n\n### Impact\nDoS and Crash\n\n### Mitigation\n* Disable the `allow_missing_or_failed` or `allow_missing`","published":"2025-12-03T18:04:35.160Z","modified":"2026-08-12T03:51:39.999178520Z","cvss":{"score":6.5,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Go","name":"github.com/envoyproxy/envoy","fixedVersion":"1.36.3"},{"ecosystem":"Go","name":"github.com/envoyproxy/envoy","fixedVersion":"1.35.7"},{"ecosystem":"Go","name":"github.com/envoyproxy/envoy","fixedVersion":"1.34.11"},{"ecosystem":"Go","name":"github.com/envoyproxy/envoy","fixedVersion":"1.33.13"}],"fix":null,"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/64xxx/CVE-2025-64527.json"},{"type":"ADVISORY","url":"https://github.com/envoyproxy/envoy/security/advisories/GHSA-mp85-7mrq-r866"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-64527"},{"type":"PACKAGE","url":"https://github.com/envoyproxy/envoy"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:39.999178520Z"}}