CVE-2025-64527 - CVE House
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Status published Medium CVE-2025-64527

Envoy crashes when JWT authentication is configured with the remote JWKS fetching

Vulnerability 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.

Impact Analysis

Refer to official advisory for detailed impact metrics.

Remediation

Ensure systems are updated to the latest vendor-supplied patch levels.

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Credits & Attribution

No credits recorded in the NVD database.

References

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Affected Vendor

Affected Software

envoy
Vulnerable Versions:
>= 1.36.0, <= 1.36.2, >= 1.35.0, <= 1.35.6, >= 1.34.0, <= 1.34.10, <= 1.33.12

Timeline

Official Publish: December 3rd, 2025
Last Modified: December 3rd, 2025
Added to House: July 22nd, 2026

CVSS Vectors

V3: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Weaknesses (CWE)

CWE-476

MITRE ATT&CK TTPs

T1499 Endpoint Denial of Service
Impact
T1499.004 Application or System Exploitation
Impact
T1489 Service Stop
Impact
T1203 Exploitation for Client Execution
Execution
T1190 Exploit Public-Facing Application
Initial Access