CVE DATABASE / CVE-2021-3156
CVE-2021-3156
Sudo Heap-Based Buffer Overflow Vulnerability
CVSS 7.8 · HIGH
⚠ CISA KEV — ACTIVELY EXPLOITED
On the CISA KEV catalog
Confirmed exploited in the wild. Added 2022-04-06.
Federal remediation due 2022-04-27.
Required action: Apply updates per vendor instructions.
Summary
Sudo before 1.9.5p2 contains an off-by-one error that can result in a heap-based buffer overflow, which allows privilege escalation to root via "sudoedit -s" and a command-line argument that ends with a single backslash character.
CVSS 3.1 breakdown
| Base score | 7.8 (HIGH) |
| Vector | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| Attack vector | LOCAL |
| Attack complexity | LOW |
| Privileges required | LOW |
| User interaction | NONE |
| Scope | UNCHANGED |
| Confidentiality | HIGH |
| Integrity | HIGH |
| Availability | HIGH |
Weakness type (CWE)
Affected products
Sudo_project sudoFedoraproject fedoraDebian debian linuxNetapp active iq unified managerNetapp cloud backupNetapp hci management nodeNetapp oncommand unified manager core packageNetapp ontap select deploy administration utilityNetapp ontap toolsNetapp solidfireMcafee web gatewaySynology diskstation manager unified controllerSynology diskstation managerSynology skynas firmwareSynology skynasSynology vs960hd firmwareSynology vs960hdBeyondtrust privilege management for macBeyondtrust privilege management for unix\/linuxOracle micros compact workstation 3 firmware
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References
- http://packetstormsecurity.com/files/161160/Sudo-Heap-Based-Buffer-Overflow.html
- http://packetstormsecurity.com/files/161230/Sudo-Buffer-Overflow-Privilege-Escalation.html
- http://packetstormsecurity.com/files/161270/Sudo-1.9.5p1-Buffer-Overflow-Privilege-Escalation.html
- http://packetstormsecurity.com/files/161293/Sudo-1.8.31p2-1.9.5p1-Buffer-Overflow.html
- http://packetstormsecurity.com/files/176932/glibc-syslog-Heap-Based-Buffer-Overflow.html
- http://seclists.org/fulldisclosure/2021/Feb/42
- http://seclists.org/fulldisclosure/2021/Jan/79
- http://seclists.org/fulldisclosure/2024/Feb/3
- http://www.openwall.com/lists/oss-security/2021/01/26/3
- http://www.openwall.com/lists/oss-security/2021/01/27/1
- http://www.openwall.com/lists/oss-security/2021/01/27/2
- http://www.openwall.com/lists/oss-security/2021/02/15/1
- http://www.openwall.com/lists/oss-security/2021/09/14/2
- http://www.openwall.com/lists/oss-security/2024/01/30/6
- http://www.openwall.com/lists/oss-security/2024/01/30/8
Data: NIST NVD + CISA KEV. NVD last modified 2025-11-10. Always verify against the vendor advisory before acting.