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Vulnerabilities/CVE-2021-3156Public Intelligence Dossier
Source: sudo project · Limited verification•Last verified: •Collection Degraded
CVE-2021-3156ListedHIGH (raw)CVSS 7.8CWE-193

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.

Published: 27 Jan 2021•Last updated: 17 Jun 2026, 09:34 AM IST•Source identifier: cve@mitre.org
Dossier completeness: source-provided sections 3 / 3 · rule guidance available. Missing source facts count as incomplete.
Official source
CISA KEV catalog
Listed
Added06 Apr 2022
Due27 Apr 2022
RansomwareUnknown
CVSS score
7.8HIGH (raw)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Metric sourcenvd@nist.gov
EPSS probability
100%1.000
Percentile100th
Weakness type
CWE-193
No further CWE recorded
Remediation
Patch status unknown
No fixed version or KB recorded

Why It Matters

Analysis dossier

Why It Matters

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.

SOC priority

Immediate Attention

Actively exploited (source statement)

Yes

Publicly disclosed

Unknown

Risk basis: CISA KEV exploitation signal; SOC ecosystem technology relevance; HIGH severity; Source-confirmed exploitation or CISA KEV/ransomware metadata

Affected Products & Remediation

24 source-backed products
Affected products and versions (source)
  • sudo project sudo · >= 1.8.2 < 1.8.32; >= 1.9.0 < 1.9.5; 1.9.5 · NVD CPE · Source
  • fedoraproject fedora · 32; 33 · NVD CPE · Source
  • debian debian linux · 9.0; 10.0 · NVD CPE · Source
  • netapp active iq unified manager · version range not provided by source · NVD CPE · Source
  • netapp cloud backup · version range not provided by source · NVD CPE · Source
  • netapp hci management node · version range not provided by source · NVD CPE · Source
  • netapp oncommand unified manager core package · version range not provided by source · NVD CPE · Source
  • netapp ontap select deploy administration utility · version range not provided by source · NVD CPE · Source
  • netapp ontap tools · 9 · NVD CPE · Source
  • netapp solidfire · version range not provided by source · NVD CPE · Source
  • mcafee web gateway · 8.2.17; 9.2.8; 10.0.4 · NVD CPE · Source
  • synology diskstation manager unified controller · 3.0 · NVD CPE · Source
  • synology diskstation manager · unified controller 3.0; 6.2 · NVD CPE · Source
  • synology skynas firmware · version range not provided by source · NVD CPE · Source
  • synology vs960hd firmware · version range not provided by source · NVD CPE · Source
  • beyondtrust privilege management for mac · < 21.1.1 · NVD CPE · Source
  • beyondtrust privilege management for unix\/linux · < 10.3.2-10 · NVD CPE · Source
  • oracle micros compact workstation 3 firmware · 310 · NVD CPE · Source
  • oracle micros es400 firmware · >= 400 <= 410 · NVD CPE · Source
  • oracle micros kitchen display system firmware · 210 · NVD CPE · Source
  • oracle micros workstation 5a firmware · 5a · NVD CPE · Source
  • oracle micros workstation 6 firmware · >= 610 <= 655 · NVD CPE · Source
  • oracle communications performance intelligence center · >= 10.3.0.0.0 <= 10.3.0.2.1; >= 10.4.0.1.0 <= 10.4.0.3.1 · NVD CPE · Source
  • oracle tekelec platform distribution · >= 7.4.0 <= 7.7.1 · NVD CPE · Source
NVD applicability prerequisites: cpe:2.3:h:synology:skynas:-:*:*:*:*:*:*:*, cpe:2.3:h:synology:vs960hd:-:*:*:*:*:*:*:*, cpe:2.3:h:oracle:micros_compact_workstation_3:-:*:*:*:*:*:*:*, cpe:2.3:h:oracle:micros_es400:-:*:*:*:*:*:*:*, cpe:2.3:h:oracle:micros_kitchen_display_system:-:*:*:*:*:*:*:*, cpe:2.3:h:oracle:micros_workstation_5a:-:*:*:*:*:*:*:*, cpe:2.3:h:oracle:micros_workstation_6:-:*:*:*:*:*:*:*. These are conditions, not proof that an environment is exposed or unaffected.
Recorded patch / KBNot provided by source

Vendor or catalog guidance (source)

  • CISA KEV: Apply updates per vendor instructions.

Known exploitation (source facts)

Only what a source states. Unknown means no source has said either way; it is not "not exploited".

CISA KEV
Listed
Exploited (source statement)
Yes
Publicly disclosed (source)
Unknown

CISA required action: Apply updates per vendor instructions.

Suggested hunting (rule-based inference)

SecOps Signal recommendation (rule-based inference). These steps are hunting hypotheses from the vulnerability class; they do not state or imply that exploitation occurred here or anywhere.

Matched local-access-review (CVSS AV:L, CVSS PR:L)

Exposure

  1. Identify hosts reporting this CVE, prioritising shared or multi-user systems.Telemetry: DeviceTvmSoftwareVulnerabilities · A local, low-privilege vector matters most where untrusted users can run code. · Rule local-access-review

Exploitation evidence

  1. Review source-stated impact and relevant application errors on affected hosts; local access alone does not establish privilege escalation.Telemetry: DeviceProcessEvents · The vector establishes local access and low privileges only. Confirm the impact from the advisory before choosing a specific hunt. · Rule local-access-review

Response

  1. Confirm the source-stated update on affected hosts.Telemetry: DeviceTvmSoftwareVulnerabilities · Host inventory can verify remediation. · Rule local-access-review

CISA KEV Record

Catalog entry
06 Apr 2022
Required action due
27 Apr 2022
Known ransomware use
Unknown

Apply updates per vendor instructions.

Change History & Source Data

— No recorded material change

CNA / source
cve@mitre.org
Record status · verification
UPDATED · CISA KEV confirmed
CPE
cpe:2.3:a:sudo_project:sudo:*:*:*:*:*:*:*:*, cpe:2.3:a:sudo_project:sudo:1.9.5:-:*:*:*:*:*:*, cpe:2.3:a:sudo_project:sudo:1.9.5:patch1:*:*:*:*:*:*, cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*, cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*, cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*, cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*, cpe:2.3:a:netapp:active_iq_unified_manager:-:*:*:*:*:vmware_vsphere:*:*, cpe:2.3:a:netapp:cloud_backup:-:*:*:*:*:*:*:*, cpe:2.3:a:netapp:hci_management_node:-:*:*:*:*:*:*:*

Evidence & Provenance

4 public sources
CISA KEV CatalogAdded 2022-04-06nvd.nist.govSource recordkc.mcafee.comSource recordlists.debian.orgSource record

Linked by the query's stored exact CVE association. Review required tables and validation status before use.

Detection Hunting Query
Target: DeviceTvmSoftwareVulnerabilities•Defender XDR
Detect endpoints exposed to CVE-2021-3156
Purpose: Exposure assessment (Category: Exposure Check)Why linked: Query metadata names CVE-2021-3156
DeviceTvmSoftwareVulnerabilities| where CveId == "CVE-2021-3156"| project DeviceId, DeviceName, OSPlatform, OSVersion, SoftwareVendor, SoftwareName, SoftwareVersion, CveId, VulnerabilitySeverityLevel, RecommendedSecurityUpdate, RecommendedSecurityUpdateId| sort by VulnerabilitySeverityLevel desc
Schema Checked · Not runtime validatedSource: SecOps Signal deterministic template · Limited verificationStatic screening: Passed structure and schema checks; tenant execution is not verified.
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Correlated briefings

SecOps Signal surfaces public advisory facts only. A missing value means the source has not published it, not that your environment is unaffected. No tenant inventory is connected.