CISA KEV · Known exploitedHigh

CVE-2021-3156

Sudo

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
7.8
EPSS
99.3%
99.9% percentile
CISA KEV
Listed
Published
2021.01.27
PRIORITY ASSESSMENT

Immediate review

CISA has listed this vulnerability in the Known Exploited Vulnerabilities catalog.

Known exploitationConfirmed by CISA KEV
Exploit probability99.3%
Technical severityCVSS 7.8

Vulnerability overview

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.

Affected product and versions

Product
Sudo
Affected versions
>= 1.8.2 < 1.8.32, >= 1.9.0 < 1.9.5, 1.9.5, 32, 33, 9.0, 10.0, 9, 8.2.17, 9.2.8, 10.0.4, 3.0, 6.2, < 21.1.1, < 10.3.2-10, 310, >= 400 <= 410, 210, 5a
Fixed versions
1.8.32, 1.9.5, 21.1.1, 10.3.2-10

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide
CISA required action

Apply updates per vendor instructions.

Due date: 2022.04.27
  1. 1
    Identify

    Confirm that Sudo and an affected version are present.

  2. 2
    Prioritize

    Combine exploitation signals with asset exposure and business criticality.

  3. 3
    Remediate

    Follow the vendor advisory or supported update path and preserve rollback options.

  4. 4
    Verify

    Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE
CWE-122, CWE-193
KEV added
2022.04.06
Ransomware use
미확인
CVE-2021-3156 — Sudo | SECUFOCUS NOW