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PatchSiren cyber security CVE debrief

CVE-2021-21193 Google CVE debrief

CVE-2021-21193 is a Google Chromium Blink use-after-free vulnerability that CISA added to the Known Exploited Vulnerabilities catalog on 2021-11-03. Because it is in the KEV catalog, defenders should treat it as an urgent patching item and follow vendor update guidance without delay.

Vendor
Google
Product
Chromium Blink
CVSS
Unknown
CISA KEV
Listed
Original CVE published
2021-11-03
Original CVE updated
2021-11-03
Advisory published
2021-11-03
Advisory updated
2021-11-03

Who should care

Security teams, endpoint administrators, and application owners responsible for Chromium Blink-based browsers or software components should prioritize this issue. Any environment that relies on Google Chromium Blink should review patch status and confirm updates are deployed.

Technical summary

The available official sources identify the issue as a use-after-free vulnerability in Google Chromium Blink. CISA’s KEV entry indicates it is a known exploited vulnerability and directs organizations to apply updates per vendor instructions. The source corpus does not provide further technical exploitation details, so defensive handling should focus on rapid remediation and exposure reduction.

Defensive priority

Urgent

Recommended defensive actions

  • Apply the vendor-recommended updates for affected Chromium Blink deployments as soon as possible.
  • Verify whether any Chromium Blink-based browsers or embedded components are present in your environment.
  • Prioritize remediation for internet-facing, user-facing, or high-risk endpoints first.
  • Track patch completion against the CISA KEV remediation due date of 2021-11-17.
  • Use standard asset inventory and vulnerability management processes to confirm all affected versions are updated.

Evidence notes

Official sources supplied in the corpus identify CVE-2021-21193 as a Google Chromium Blink use-after-free vulnerability. CISA’s Known Exploited Vulnerabilities catalog added it on 2021-11-03 and set a remediation due date of 2021-11-17. No CVSS score was provided in the supplied record, and the corpus does not include exploit mechanics beyond the use-after-free classification.

Sources and references

Verified primary and authoritative sources

  • CVE-2021-21193 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2021-21193

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

  • CVE-2021-21193 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2021-21193

    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.