CVE-2026-109706 Mozilla CVE debrief

Who should care

Defenders responsible for Firefox deployments, especially those using versions prior to 158, Firefox ESR 115.43, or Firefox ESR 153.5, should assess exposure and prioritize updates or compensating controls.

Why it matters

Defenders should prioritize verifying exposure in Firefox deployments, especially those using versions prior to 158, Firefox ESR 115.43, or Firefox ESR 153.5, and assess the need for updates due to a use-after-free vulnerability in the Storage: IndexedDB component.

• Verification of Firefox version and potential updates to prevent exploitation.
• Assessment of exposure in Firefox deployments to prioritize remediation.
• Implementation of compensating controls if updates cannot be applied immediately.

Technical summary

A use-after-free vulnerability exists in the Storage: IndexedDB component of Firefox. This vulnerability was fixed in Firefox 158, Firefox ESR 115.43, and Firefox ESR 153.5. The vulnerability affects Firefox deployments, especially those using versions prior to 158, Firefox ESR 115.43, or Firefox ESR 153.5. Defenders should prioritize verifying exposure in Firefox deployments and assess the need for updates. The CVE record and source corpus indicate a use-after-free vulnerability in the Storage: IndexedDB component of Firefox, but specific details about exploitation or impact are not provided.

Defensive priority

Defenders should prioritize verifying exposure in Firefox deployments, especially those using versions prior to 158, Firefox ESR 115.43, or Firefox ESR 153.5, and assess the need for updates.

Recommended defensive actions

• Verify Firefox version and update to 158, Firefox ESR 115.43, or Firefox ESR 153.5 if necessary.
• Assess exposure in Firefox deployments.
• Review and implement compensating controls if updates cannot be applied immediately.
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up.
• Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance.
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed.
• Check relevant monitoring, detection, and logs for exposed assets that need extra review.

Evidence notes

The CVE record and source corpus indicate a use-after-free vulnerability in the Storage: IndexedDB component of Firefox, which was fixed in Firefox 158, Firefox ESR 115.43, and Firefox ESR 153.5. However, specific details about exploitation or impact are not provided.

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.