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CVE-2021-3156

HIGH
7.8
CVSS Score
Published: January 26, 2021 at 12:00 AM UTC
Updated: June 17, 2026 at 04:04 AM UTC
31 products affected across 8 vendorsDebian LinuxFedoraActive IQ Unified Manager

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Severity
HIGH7.8
Exploitation
CISA KEV
Exploit prediction
EPSS 100%
SSVC
Active

Actively Exploited

CISA Known Exploited Vulnerabilities (KEV) Catalog

EPSS Score100.0%

EPSS (Exploit Prediction Scoring System) estimates a 100.0% chance this CVE is exploited in the wild within the next 30 days — higher than 100% of all CVEs. It complements CVSS: a high EPSS on a mid-severity CVE can still be urgent.

Sudo contains an off-by-one error that can result in a heap-based buffer overflow, which allows for privilege escalation.

Required Action
Apply updates per vendor instructions.
Ransomware Use
Unknown
Added to KEV
Apr 6, 2022
Remediation Due
Apr 27, 2022
1643 days overdue
Notes
https://nvd.nist.gov/vuln/detail/CVE-2021-3156

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Privilege Management for Mac· Beyondtrust
95%
v < 21.1.1
Affected range stops below 21.1.1, so it looks safe — our inference, not a vendor statement
Privilege Management for Unix /linux· Beyondtrust
95%
v < 10.3.2-10
Affected range stops below 10.3.2-10, so it looks safe — our inference, not a vendor statement
Debian Linux· Debiandrupal
95%
10.09.0
Fedora· Fedora Projectrpm
95%
3233
Web Gateway· McAfee
95%
10.0.48.2.179.2.8
Active IQ Unified Manager· NetAppnpm
95%
All versions
Cloud Backup· NetAppdrupal
95%
All versions
Hci Management Node· NetApp
95%
All versions
Oncommand Unified Manager Core Package· NetApp
95%
All versions
ONTAP Select Deploy administration utility· NetApp
95%
All versions

References (35)

ExploitThird Party AdvisoryVDB Entry
Source: [email protected]
http://packetstormsecurity.com/files/161160/Sudo-Heap-Based-Buffer-Overflow.html
ExploitThird Party AdvisoryVDB Entry
Source: [email protected]
http://packetstormsecurity.com/files/161230/Sudo-Buffer-Overflow-Privilege-Escalation.html
ExploitThird Party AdvisoryVDB Entry
Source: [email protected]
http://packetstormsecurity.com/files/161270/Sudo-1.9.5p1-Buffer-Overflow-Privilege-Escalation.html
ExploitThird Party AdvisoryVDB Entry
Source: [email protected]
http://packetstormsecurity.com/files/161293/Sudo-1.8.31p2-1.9.5p1-Buffer-Overflow.html
ExploitThird Party AdvisoryVDB Entry
Source: [email protected]
http://packetstormsecurity.com/files/176932/glibc-syslog-Heap-Based-Buffer-Overflow.html
Mailing ListThird Party Advisory
Source: [email protected]
http://seclists.org/fulldisclosure/2021/Feb/42
Mailing ListExploitThird Party Advisory
Source: [email protected]
http://seclists.org/fulldisclosure/2021/Jan/79
Mailing ListExploitThird Party Advisory
Source: [email protected]
http://seclists.org/fulldisclosure/2024/Feb/3

SSVC — Action Prioritization

SSVCActiveNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.8HIGHCISA-ADP
Attack Vector
LOCAL
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-193

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