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 wit…

Not analysed yet

We haven’t published our own analysis of this CVE. If a person reviews it, this page will say what’s affected and what has to be true for it to matter.

Severity and exploitation

• CISA KEV Listed since 6 Apr 2022: known to be exploited.
• EPSS 1.00, the 99th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

This record came from the full history of the CVE Program, published 26 Jan 2021. New records show when each source confirmed them.

Sources

• CVE List: CVE-2021-3156
• NVD: CVE-2021-3156

References from the CNA

• lists.debian.org/debian-lts-announce/2021/01/msg00022.html mailing-list
• seclists.org/fulldisclosure/2021/Jan/79 mailing-list
• www.openwall.com/lists/oss-security/2021/01/26/3 mailing-list
• security.gentoo.org/glsa/202101-33 vendor-advisory
• www.debian.org/security/2021/dsa-4839 vendor-advisory
• lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LHXK6ICO5AYLGFK2TAX5MZKUXTUKWOJY/ vendor-advisory
• lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CALA5FTXIQBRRYUA2ZQNJXB6OQMAXEII/ vendor-advisory
• www.openwall.com/lists/oss-security/2021/01/27/1 mailing-list
• www.openwall.com/lists/oss-security/2021/01/27/2 mailing-list
• tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sudo-privesc-jan2021-qnYQfcM vendor-advisory
• www.kb.cert.org/vuls/id/794544 third-party-advisory
• seclists.org/fulldisclosure/2021/Feb/42 mailing-list
• www.openwall.com/lists/oss-security/2021/02/15/1 mailing-list
• www.oracle.com//security-alerts/cpujul2021.html
• www.sudo.ws/stable.html#1.9.5p2
• www.openwall.com/lists/oss-security/2021/01/26/3
• packetstormsecurity.com/files/161160/Sudo-Heap-Based-Buffer-Overflow.html
• security.netapp.com/advisory/ntap-20210128-0002/
• security.netapp.com/advisory/ntap-20210128-0001/
• packetstormsecurity.com/files/161230/Sudo-Buffer-Overflow-Privilege-Escalation.html
• packetstormsecurity.com/files/161270/Sudo-1.9.5p1-Buffer-Overflow-Privilege-Escalation.html
• packetstormsecurity.com/files/161293/Sudo-1.8.31p2-1.9.5p1-Buffer-Overflow.html
• support.apple.com/kb/HT212177
• kc.mcafee.com/corporate/index?page=content&id=SB10348
• www.beyondtrust.com/blog/entry/security-advisory-privilege-management-for-unix-linux-pmul-basic-and-privilege-management-for-mac-pmm-affected-by-sudo-vulnerability
• www.synology.com/security/advisory/Synology_SA_21_02
• www.openwall.com/lists/oss-security/2021/09/14/2 mailing-list
• www.oracle.com/security-alerts/cpuoct2021.html
• www.oracle.com/security-alerts/cpuapr2022.html
• www.openwall.com/lists/oss-security/2024/01/30/8 mailing-list

And 4 more on the CVE record.

Facts on this page come from the CVE List as the CNA published them, with CVSS from the sources named above, CISA KEV and FIRST EPSS. Vendors, products and versions are shown as the CNA wrote them. We don’t reproduce the CVE’s description.