NULL pointer dereference in Envoyproxy Envoy
CVE-2025-64527
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.
EPSS: 0.005 (40.4th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.
Affected products
- Envoyproxy Envoy — versions >= 1.36.0, <= 1.36.2, >= 1.35.0, <= 1.35.6, >= 1.34.0, <= 1.34.10
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Exploit, Vendor Advisory)
Frequently asked questions
- What is CVE-2025-64527?
- CVE-2025-64527 is a medium-severity vulnerability in Envoyproxy Envoy, classified under NULL Pointer Dereference. CVSS score: 6.5/10. Published 2025-12-03.
- How severe is CVE-2025-64527?
- Medium severity. CVSS v3 base score is 6.5 out of 10.