Improper access control in envoy - CVE-2021-21378
Published: March 9, 2021 / Updated: August 26, 2026
Vulnerability identifier: #VU145853
CSH Severity: High
CVSS v4: 8.8 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2021-21378
CWE-ID: CWE-284
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to disclose sensitive information.
The vulnerability exists due to improper access control in JWT authentication when validating tokens with an unknown issuer. A remote attacker can present a token with an unknown issuer to disclose sensitive information.
Affected software
envoy
How to mitigate CVE-2021-21378
Install security update from vendor's website.
envoy - update to 1.17.1