CVE-2026-109744 Mozilla CVE debrief

Who should care

Defenders responsible for managing Mozilla Firefox deployments should assess exposure and apply patches as necessary. Affected operators, platforms, and security teams should prioritize verifying exposure and applying patches to prevent potential issues. Vulnerability management and security teams should review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance.

Why it matters

CVE-2026-109744 is a vulnerability in the DOM: File component of Mozilla Firefox. Defenders should prioritize verifying exposure and applying patches to prevent potential issues.

• Verify exposure in Firefox deployments
• Apply patches to prevent potential issues
• Monitor Firefox deployments for potential issues

Technical summary

The vulnerability, CVE-2026-109744, is an issue in the DOM: File component of Mozilla Firefox. It was fixed in Firefox 158 and Firefox ESR 153.5. Defenders should prioritize verifying exposure in their Firefox deployments and applying the available patches. The vulnerability affects Mozilla Firefox deployments, and defenders should assess exposure and apply patches as necessary to prevent potential issues. The CVE record and Mozilla advisories provide limited information about the vulnerability, and further investigation is required to determine the full scope of the issue.

Defensive priority

Defenders should prioritize verifying exposure in their Firefox deployments and applying the available patches.

Recommended defensive actions

• Verify Firefox version and apply patches if necessary
• Review Mozilla advisories for additional information
• Monitor Firefox deployments for potential issues
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented

Evidence notes

The CVE record and Mozilla advisories provide limited information about the vulnerability. Further investigation is required to determine the full scope of the issue. Defenders should verify exposure in their Firefox deployments and apply available patches. The vulnerability is an issue in the DOM: File component of Mozilla Firefox. The CVE record was published on 2026-10-13T12:29:27.136Z and has not been modified since then. Evidence limits and source grounding are necessary to understand the vulnerability.

Sources and 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.