NULL pointer dereference in envoy - CVE-2021-43824
Published: February 22, 2022 / Updated: August 26, 2026
Vulnerability identifier: #VU145846
CSH Severity: Medium
CVSS v4: 6.7 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2021-43824
CWE-ID: CWE-476
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 null pointer dereference in the JWT filter safe_regex match functionality when processing crafted input. A remote attacker can trigger the vulnerable code path to cause a denial of service.
User interaction is required to process the crafted input.
Affected software
envoy
How to mitigate CVE-2021-43824
Install security update from vendor's website.
envoy - addressed in versions 1.18.6, 1.19.3, 1.20.2, 1.21.1