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CVE-2026-109750 Mozilla CVE debrief

A site isolation issue in the DOM: Web Authentication component was reported in Mozilla Firefox. This vulnerability was fixed in Firefox 158. The issue involves a site isolation problem in the Web Authentication component of Mozilla Firefox, which could potentially impact the security of user authentication processes. Defenders responsible for managing Mozilla Firefox deployments should assess their current versions and update to version 158 or later to mitigate potential risks associated with this 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 Mozilla Firefox deployments should assess their current versions and update to version 158 or later to mitigate potential risks associated with this vulnerability.

Why it matters

Defenders should care about this CVE because it involves a site isolation issue in the Web Authentication component of Mozilla Firefox, which could potentially impact the security of user authentication processes. The vulnerability was fixed in Firefox 158, so defenders need to ensure their deployments are up-to-date to mitigate potential risks.

  • Verification of Firefox version for exposure assessment
  • Potential impact on Web Authentication component functionality

Technical summary

A site isolation issue was reported in the DOM: Web Authentication component of Mozilla Firefox. This issue was addressed and fixed in Firefox version 158. The vulnerability could potentially impact the security of user authentication processes. Defenders need to ensure their deployments are up-to-date to mitigate potential risks. Verification of Firefox version for exposure assessment and potential impact on Web Authentication component functionality are recommended.

Defensive priority

Defenders should prioritize verifying if their Firefox versions are up-to-date, specifically checking for version 158 or later, and assess exposure based on their current browser deployment.

Recommended defensive actions

  • Verify Firefox version and update to version 158 or later if necessary
  • Assess exposure based on current browser deployment
  • Monitor for any potential impacts related to Web Authentication component

Evidence notes

The CVE record and source item provide limited information about the vulnerability, with the primary details coming from the Mozilla source reference.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-109750 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-109750

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

  • CVE-2026-109750 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-109750

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

Supplemental references

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.