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.

Metrics

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploitation none

Automatable no

Technical Impact partial

Affected Vendors & Products

Vendors Products
Envoyproxy
  • Envoy

Configuration 1 [-]

OR cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*
cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*
cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*
cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*

No data.

References
Link Providers
https://github.com/envoyproxy/envoy/security/advisories/GHSA-mp85-7mrq-r866 cve-icon cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2025-64527 cve-icon
https://www.cve.org/CVERecord?id=CVE-2025-64527 cve-icon
History

Fri, 05 Dec 2025 17:00:00 +0000

Type Values Removed Values Added
CPEs cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*

Thu, 04 Dec 2025 16:45:00 +0000

Type Values Removed Values Added
First Time appeared Envoyproxy
Envoyproxy envoy
Vendors & Products Envoyproxy
Envoyproxy envoy

Thu, 04 Dec 2025 12:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-248
References
Metrics threat_severity

None

 threat_severity

Moderate

Wed, 03 Dec 2025 21:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Wed, 03 Dec 2025 18:15:00 +0000

Type Values Removed Values Added
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.
Title Envoy crashes when JWT authentication is configured with the remote JWKS fetching
Weaknesses CWE-476
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}
cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published: 2025-12-03T18:04:35.160Z

Updated: 2025-12-03T20:18:19.588Z

Reserved: 2025-11-05T21:15:39.401Z

Link: CVE-2025-64527

cve-icon Vulnrichment

Updated: 2025-12-03T20:18:15.687Z

cve-icon NVD

Status : Analyzed

Published: 2025-12-03T18:15:46.863

Modified: 2025-12-05T16:56:40.850

Link: CVE-2025-64527

cve-icon Redhat

Severity : Moderate

Publid Date: 2025-12-03T12:00:00Z

Links: CVE-2025-64527 - Bugzilla