CVE-2026-6765 Mozilla CVE debrief

Who should care

Defenders responsible for systems using Firefox, Thunderbird, and related deployment contexts should assess exposure and prioritize patching to mitigate potential information disclosure risks.

Why it matters

The CVE-2026-6765 vulnerability is an information disclosure issue in the Form Autofill component of Firefox, which was fixed in Firefox 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10. Defenders should assess exposure for systems using the affected versions and prioritize patching to mitigate potential risks.

• Defenders should verify and apply patches to mitigate potential information disclosure risks.
• Assess exposure for systems using affected versions of Firefox and Thunderbird.
• Monitor for potential information disclosure risks in related deployment contexts.

Technical summary

The CVE-2026-6765 vulnerability is an information disclosure issue in the Form Autofill component of Firefox. It has a CVSS score of 5.3 and a severity of MEDIUM. The vulnerability was fixed in Firefox 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10. Defenders should prioritize verifying and applying the provided patches for Firefox, Thunderbird, and related systems to mitigate potential information disclosure risks. The vulnerability affects systems using the affected versions of Firefox and Thunderbird.

Defensive priority

Defenders should prioritize verifying and applying the provided patches for Firefox, Thunderbird, and related systems to mitigate potential information disclosure risks.

Recommended defensive actions

• Verify and apply patches for Firefox 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.
• Assess exposure for systems using affected versions of Firefox and Thunderbird.
• Monitor for potential information disclosure risks in related deployment contexts.
• 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.
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up.

Evidence notes

The CVE record and NVD entry provide details on the vulnerability, its CVSS score, and affected software versions. Vendor advisories from Mozilla offer guidance on patched versions. The vulnerability affects Firefox, Thunderbird, and related deployment contexts. Defenders should verify and apply patches to mitigate potential information disclosure risks. The CVE Program and NVD provide official records and assessments.

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.