CVE-2021-3156VulnerabilityPublished 04/06/2022Updated 10/24/2026
CVE-2021-3156: Sudo Heap-Based Buffer Overflow Vulnerability
Affects Sudo SudoSource CISA KEV
Severity
HighNo CVSS score published yet
- Exploitation
Actively exploited – in CISA KEV since 04/06/2022
- KEV deadline
- 04/27/2022
- EPSS
- 100.0% chance of exploitation in 30 days – higher than 99% of CVEs
What to do
CISA required action
Apply updates per vendor instructions.
Description
CVE-2021-3156 is a heap-based buffer overflow vulnerability in Sudo caused by an off-by-one error. This flaw allows an attacker to escalate privileges on affected systems. It has been exploited in the wild, indicating active threat usage. The vulnerability is rated as high severity due to its potential impact on system security.