Reachable assertion in envoy - CVE-2021-29258
Published: April 16, 2021 / Updated: August 26, 2026
Vulnerability identifier: #VU145852
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2021-29258
CWE-ID: CWE-617
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to a reachable assertion in HTTP/2 METADATA handling when processing an empty METADATA map. A remote attacker can send a specially crafted HTTP/2 request to cause a denial of service.
Affected software
envoy
How to mitigate CVE-2021-29258
Install security update from vendor's website.
envoy - addressed in versions 1.14.7, 1.15.4, 1.16.3, 1.17.2, 1.18.0