CVE-2025-64527
Envoy crashes when JWT authentication is configured with the remote JWKS fetching
Description
Envoy is a high-performance edge/middle/service proxy. In 1.33.12, 1.34.10, 1.35.6, 1.36.2, and earlier, Envoy 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. This 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. The original callback's reset() then clears the second fetch's state (receiver_ and request_) which causes a crash when the async HTTP response arrives.
How to fix CVE-2025-64527
To remediate CVE-2025-64527, upgrade the affected package to a fixed version below.
- —upgrade to 1.33.13 or later
- —upgrade to 1.36.3 or later
Is CVE-2025-64527 being exploited?
Low — EPSS is 0.0%, meaning exploitation activity has not been observed at scale.
Affected packages (2)
- from 0, < 1.33.13, >= 1.34.0, < 1.34.11, >= 1.35.0, < 1.35.7, >= 1.36.0, < 1.36.3
- >= 1.36.0, < 1.36.3
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | MEDIUM6.5 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |