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CVE-2026-109779 Mozilla CVE debrief

A race condition vulnerability in the Networking: DNS component of Firefox was fixed in version 158. This issue requires verification of affected versions and potential exposure. The vulnerability was publicly disclosed and patched, and defenders should review the Mozilla security advisory for more information. Affected Firefox versions prior to 158 should be verified for potential exposure, and assessments of DNS-related issues in Firefox are necessary. The CVE record and source item provide limited information about the vulnerability.

Vendor
Mozilla
Product
Firefox
CVSS
Unknown
CISA KEV
Not listed in stored evidence
Original CVE published
2026-10-13
Original CVE updated
2026-10-13
Advisory published
2026-10-13
Advisory updated
2026-10-13

Who should care

Defenders responsible for managing Firefox deployments should verify their versions and assess potential exposure to this vulnerability. This includes reviewing the Mozilla security advisory and CVE record for more information. Affected operators, platforms, and security teams should prioritize verification of Firefox versions prior to 158 and assess potential exposure. Vulnerability management and security teams are

Why it matters

A race condition vulnerability in Firefox's Networking: DNS component requires verification of affected versions and potential exposure.

  • Verification of Firefox versions prior to 158 is necessary to determine potential exposure
  • Assessment of DNS-related issues in Firefox is required

Technical summary

A race condition vulnerability exists in the Networking: DNS component of Firefox. This issue was fixed in Firefox version 158. The vulnerability requires verification of affected versions and potential exposure. The Mozilla Bugzilla entry and security advisory provide additional information about the vulnerability. Defenders should verify if their Firefox versions are prior to 158 and assess potential exposure to this vulnerability.

Defensive priority

Defenders should verify if their Firefox versions are prior to 158 and assess potential exposure to this vulnerability.

Recommended defensive actions

  • Verify Firefox version and update to 158 or later if necessary
  • Assess potential exposure to this vulnerability
  • Monitor for potential DNS-related issues in Firefox

Evidence notes

The CVE record and source item provide limited information about the vulnerability, with the primary source being the Mozilla Bugzilla entry and security advisory.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-109779 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-109779

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

  • CVE-2026-109779 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-109779

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

Supplemental references

  • Race condition in the Networking: DNS component

    Unverified legacy reference

    URL: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/109xxx/CVE-2026-109779.json

    cve_program_cvelist_v5

  • Source reference

    Unverified legacy reference

    URL: https://www.mozilla.org/security/advisories/mfsa2026-106/

    Supplemental source

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.