CVE Tools
Sign in

CVE-2025-64527

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

Published: Dec 3, 2025Updated: Dec 5, 2025 Sources: CVE List NVD GHSACWE-476
NVD MITRE
6.5CVSSMEDIUM
EPSS Score
0.5%
Top 62.5%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available

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.

CVSS Vector Breakdown

AV:NAC:LPR:LUI:NS:UC:NI:NA:H
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:LPrivileges Required
Low
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:NIntegrity
None
A:HAvailability
High
Open in CVSS calculator →

Weaknesses

CWE-476

Affected Products

envoyenvoyproxy
On-prem
Cloud & SaaS / api-gateway
github.com/envoyproxy/envoyGoOSS Libraries
envoyproxyoss-projectUSCloud & SaaSaka envoy proxy, envoy
gopackage-ecosystemOSS Libraries

Attack Graph

Products CVE Techniques Tactics

Click technique nodes to view MITRE ATT&CK details. Scroll to zoom, drag to pan.

Exploitability

Official Patch Available

MITRE ATT&CK

2 techniques
Impact
Initial Access
View detailed technique mapping

References

https://github.com/envoyproxy/envoy/security/advisories/GHSA-mp85-7mrq-r866
github.com
https://nvd.nist.gov/vuln/detail/CVE-2025-64527
nvd.nist.gov
https://github.com/envoyproxy/envoy
github.com

Timeline

Published
Dec 3, 2025
Last Updated
Dec 5, 2025

Unlock Complete Vulnerability Intelligence

Get the full picture for CVE-2025-64527 and every CVE in our database. Create a free account — no credit card required.

Create Free Account
Plain-language analysis
Impact assessment and exploitation scenario in plain English
Attack graph visualization
Interactive attack path and kill chain mapping
Exploit details & PoC links
ExploitDB, Metasploit, GitHub PoCs with direct links
Nuclei scanner templates
Ready-to-use vulnerability scanner templates
Full remediation guide
Patch instructions, workarounds, and compliance impact
Interactive AI chat
Ask questions about this vulnerability in natural language
Related vulnerabilities
Semantically similar CVEs and attack patterns
REST API & MCP access
Integrate vulnerability data into your workflows