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PatchSiren cyber security CVE debrief

CVE-2021-3156 Sudo CVE debrief

CVE-2021-3156 is a sudo heap-based buffer overflow vulnerability that CISA has added to its Known Exploited Vulnerabilities catalog. Because it is listed as known exploited, organizations should treat it as a priority patching issue and follow vendor remediation guidance promptly.

Vendor
Sudo
Product
Sudo
CVSS
HIGH 7
CISA KEV
Listed
Original CVE published
2022-04-06
Original CVE updated
2022-04-06
Advisory published
2022-04-06
Advisory updated
2022-04-06

Who should care

Linux administrators, endpoint and server operations teams, vulnerability management owners, and incident response teams responsible for systems that include sudo.

Technical summary

The available source corpus identifies CVE-2021-3156 as a heap-based buffer overflow in sudo. CISA’s Known Exploited Vulnerabilities catalog marks it as actively exploited and instructs affected organizations to apply updates per vendor instructions. The supplied data does not include a CVSS score, so prioritization should be driven by the KEV status and exposure of affected systems.

Defensive priority

High. CISA has classified this CVE as known exploited and assigned a remediation due date of 2022-04-27 in the KEV catalog, making timely patching and verification important.

Recommended defensive actions

  • Inventory systems that include sudo and confirm affected package versions.
  • Apply the vendor-provided updates or mitigations as soon as possible.
  • Track remediation against the CISA KEV due date and verify completion across the fleet.
  • Re-scan systems after patching to confirm the vulnerable version is no longer present.
  • Review monitoring and incident response logs for any indicators of abuse on exposed systems.

Evidence notes

This debrief is based only on the supplied CISA KEV source item and official resource links. The KEV metadata states: vendorProject Sudo, product Sudo, vulnerabilityName 'Sudo Heap-Based Buffer Overflow Vulnerability,' dateAdded 2022-04-06, dueDate 2022-04-27, and requiredAction 'Apply updates per vendor instructions.' The official resource links provided are the CVE record, NVD detail page, and CISA KEV catalog entry.

Sources and references

Verified primary and authoritative sources

  • CVE-2021-3156 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2021-3156

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2021-3156 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2021-3156

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

  • CISA Known Exploited Vulnerabilities catalog

    Publisher, destination, and source semantics verified

    URL: https://www.cisa.gov/known-exploited-vulnerabilities-catalog

    Cybersecurity and Infrastructure Security Agency - Official CISA catalog of vulnerabilities known to be exploited in the wild.

Supplemental references

  • Source item URL

    Unverified legacy reference

    URL: https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json

    cisa_kev

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.