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PatchSiren cyber security CVE debrief

CVE-2021-3493 Linux CVE debrief

CVE-2021-3493 is a Linux kernel privilege escalation vulnerability that CISA has placed in the Known Exploited Vulnerabilities catalog. That KEV listing indicates the issue has been observed in active exploitation, so defenders should treat Linux kernel patching and verification as a priority. The supplied official sources do not provide affected versions or deeper technical root-cause details, so remediation guidance here is limited to the vendor-directed update path referenced by CISA.

Vendor
Linux
Product
Kernel
CVSS
HIGH 8.8
CISA KEV
Listed
Original CVE published
2022-10-20
Original CVE updated
2022-10-20
Advisory published
2022-10-20
Advisory updated
2022-10-20

Who should care

Linux administrators, endpoint and server fleet owners, vulnerability management teams, and security operations teams responsible for Linux kernel patching.

Technical summary

Based on the supplied official sources, CVE-2021-3493 is identified as a Linux kernel privilege escalation vulnerability and is listed by CISA as a known exploited vulnerability. CISA’s metadata directs organizations to apply updates per vendor instructions. The provided corpus does not include affected kernel versions, exploit mechanics, or a technical root cause.

Defensive priority

High

Recommended defensive actions

  • Identify Linux systems running the affected kernel line in your environment and confirm exposure status against vendor advisories.
  • Apply the vendor-recommended kernel updates as soon as practical; CISA’s KEV entry says to apply updates per vendor instructions.
  • Verify patch deployment by checking installed kernel versions and reboot status where required.
  • Prioritize remediation on systems with elevated privilege exposure, broad administrative access, or operational criticality.
  • Use the official CISA KEV catalog and vendor release notes to track remediation progress and validate closure.

Evidence notes

The debrief is based only on the supplied official source corpus: the CISA KEV feed entry, the CVE record, and the NVD detail page referenced by that entry. The corpus confirms the CVE is a Linux kernel privilege escalation vulnerability and that CISA classified it as known exploited; it does not supply affected versions, a CVSS score, or exploit details. Timing references follow the provided metadata: CVE published/modified date 2022-10-20 and CISA KEV date added 2022-10-20.

Sources and references

Verified primary and authoritative sources

  • CVE-2021-3493 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2021-3493

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

  • CVE-2021-3493 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2021-3493

    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.