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CVE-2021-3156

7.8 · HIGHActively Exploited

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 w…

Published Jan 26, 2021CWE-193EPSS 99.96%

Overview

CVE-2021-3156 is a high-severity vulnerability. It was published on January 26, 2021 and has a CVSS 3.1 base score of 7.8 (HIGH). This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog, indicating active exploitation in the wild.

This vulnerability has a CVSS 3.1 base score of 7.8, rated HIGH. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.

Technical description

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.

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References

Refpacketstormsecurity.com/files/161160/Sudo-Heap-Based-Buffer-Overflow.htmlRefpacketstormsecurity.com/files/161230/Sudo-Buffer-Overflow-Privilege-Escalation.htmlRefpacketstormsecurity.com/files/161270/Sudo-1.9.5p1-Buffer-Overflow-Privilege-Escalation.htmlRefpacketstormsecurity.com/files/161293/Sudo-1.8.31p2-1.9.5p1-Buffer-Overflow.htmlRefpacketstormsecurity.com/files/176932/glibc-syslog-Heap-Based-Buffer-Overflow.htmlRefseclists.org/fulldisclosure/2021/Feb/42Refseclists.org/fulldisclosure/2021/Jan/79Refseclists.org/fulldisclosure/2024/Feb/3Refwww.openwall.com/lists/oss-security/2021/01/26/3Refwww.openwall.com/lists/oss-security/2021/01/27/1

How CyberStrike helps

Frequently asked questions

What is CVE-2021-3156?

CVE-2021-3156 is a high-severity vulnerability. It was published on January 26, 2021 and has a CVSS 3.1 base score of 7.8 (HIGH). This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog, indicating active exploitation in the wild.

How severe is CVE-2021-3156?

This vulnerability has a CVSS 3.1 base score of 7.8, rated HIGH. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.

How do I fix or remediate CVE-2021-3156?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2021-3156?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2021-3156 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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