Vulnerability report

Exploited in the wild Confirmed confidence In CISA KEV

CVE-2021-3156

Sudo Privilege Escalation

Sudo Project / Sudo

Watch CVE-2021-3156 Browse KEV feed
Severity
CVSS 7.8 · High
Confidence
Confirmed
Exploit status
Exploited in the wild
EPSS
100.0%
First observed
—
Last observed
—

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2021-3156 is a vulnerability affecting Sudo Project 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...

Is it exploited?

Yes. Previdian tracks this CVE as a known exploited vulnerability. Confidence is confirmed. Listed in CISA KEV.

Who is affected?

Sudo Project / Sudo.

What should we do?

Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.

Overview

Sudo Privilege Escalation

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.

View vendor advisory (opens in new tab)
Published
26 Jan 2021
Exploitation Reported
06 Apr 2022
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None

Tags

cisa metasploit

CVE References

Exploitation evidence

Why Previdian marks this CVE as exploited

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploited in the wild

CISA

Recorded 06 Apr 2022

A trusted third party reported exploitation.

Proof of concept available

GitHub

Recorded 27 Jan 2021

Public scanner or PoC coverage increases practical exploitability.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the Previdian Pro API.

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Source Added
CISA First 2022-04-06 00:00 UTC

Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Observed signals

Request targets
User-Agents
Callback hosts
0
0
0

Request targets and User-Agents available in Pro. Callback host details available in Enterprise.

Virtual patch status

No Previdian virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.

Learn about virtual patches →

Scanner Artifacts

Scanner and exploit-framework references linked to this CVE.

Scanner Reference Detected
Metasploit https://github.com/rapid7/metasploit-framework/blob/master/modules/exploits/linux/local/sudo_baron_samedit.rb 28 Apr 2025

Risk and context

Severity, weaknesses, and research context

CVSS v3.1

7.8 High

Potential damage if exploited. Separate from whether attackers are using it.

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS

100.0%

Estimated chance of exploitation in the next 30 days. Previdian's warning comes from evidence, not this score.

Weaknesses

Off-by-one Error CWE-193

Recent mention · RecordedFuture

August 2026 CVE Landscape

In August 2026, Insikt Group® identified 73 high-impact vulnerabilities that should be prioritized for remediation, 43 of which had a Very Critical Recorded Future Risk Score. This represents a 14% decrease from last month.

Read full advisory

All CVSS Scores

CVSS v3.1 7.8 High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS v2.0 7.2 High

AV:L/AC:L/Au:N/C:C/I:C/A:C

Potential Proof of Concepts

These PoCs are unverified and could contain malware. Use at your own risk.

worawit/CVE-2021-3156

github · Created 2021-03-15 17:37:02 UTC · 746 stars · AI assessment 90%

Sudo Baron Samedit Exploit

Rvn0xsy/CVE-2021-3156-plus

github · Created 2021-02-09 19:25:18 UTC · 201 stars · AI assessment 90%

CVE-2021-3156非交互式执行命令

0xdevil/CVE-2021-3156

github · Created 2021-02-08 18:21:58 UTC · 51 stars · AI assessment 90%

CVE-2021-3156: Sudo heap overflow exploit for Debian 10

CptGibbon/CVE-2021-3156

github · Created 2021-02-03 19:57:56 UTC · 151 stars · AI assessment 90%

Root shell PoC for CVE-2021-3156

blasty/CVE-2021-3156

github · Created 2021-01-30 20:39:58 UTC · 975 stars · AI assessment 90%

stong/CVE-2021-3156

github · Created 2021-01-30 03:22:04 UTC · 435 stars · AI assessment 90%

PoC for CVE-2021-3156 (sudo heap overflow)

reverse-ex/CVE-2021-3156

github · Created 2021-01-27 16:03:34 UTC · 111 stars · AI assessment 85%

CVE-2021-3156

sudo_baron_samedit

metasploit · Created Unknown

Metasploit module for CVE-2021-3156

Timeline

From disclosure to observed exploitation

  1. 15:02 UTC

    Metasploit module available

    Exploit module available

  2. 00:00 UTC

    Added to CISA KEV

    Listed in the CISA Known Exploited Vulnerabilities catalog

  3. 16:03 UTC

    Public PoC available

    Public proof-of-concept code published

  4. 00:00 UTC

    CVE published

    Vulnerability disclosed publicly

  5. 00:00 UTC

    CVE ID reserved

    Identifier reserved by the CNA

Pro API

Automate this intelligence

Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

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  • Evidence confidence and provenance
  • First-party sensor telemetry
  • PoC and scanner references
  • Affected versions and enrichment
  • Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2021-3156

Free JSON includes basic KEV fields 
{
  "cve_id": "CVE-2021-3156",
  "confidence": "Confirmed",
  "cvss_score": 7.8,
  "cvss_estimated": false,
  "epss_score": 0.99962,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": false
  },
  "sensor_telemetry": { "attempts": 0, "sensors": 0 }
}