CVE-2026-92030 Mozilla CVE debrief

Who should care

Defenders responsible for managing and securing Firefox, Firefox ESR, and Thunderbird installations should assess exposure and apply patches accordingly. This includes reviewing system configurations, monitoring for suspicious activity, and verifying patch application to prevent potential security risks. Operators, platform administrators, vulnerability management teams, and security teams should be aware of the vulnerability and take necessary actions to

Why it matters

CVE-2026-92030 is a mitigation bypass vulnerability in the DOM: Copy & Paste and Drag & Drop component of Firefox, Firefox ESR, and Thunderbird. Defenders should verify and apply patches, review system configurations, and monitor for suspicious activity.

• Verification of patch application is necessary to prevent potential security risks
• Defenders should assess exposure and apply patches for affected systems
• Monitoring for suspicious activity related to the affected components is recommended

Technical summary

The DOM: Copy & Paste and Drag & Drop component in Firefox, Firefox ESR, and Thunderbird has a mitigation bypass vulnerability. This issue allows for potential security risks if exploited. The vulnerability was addressed in Firefox 156, Firefox ESR 140.16, Firefox ESR 153.3, Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.3. Defenders should prioritize verifying and applying patches for affected systems, particularly those using Firefox, Firefox ESR, and Thunderbird. The CVE record and NVD entry provide details on the vulnerability, including its description, CVSS score, and affected products.

Defensive priority

Defenders should prioritize verifying and applying patches for affected systems, particularly those using Firefox, Firefox ESR, and Thunderbird.

Recommended defensive actions

• Verify and apply patches for Firefox, Firefox ESR, and Thunderbird
• Review system configurations and update to the latest versions
• Monitor for any suspicious activity related to the affected components
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed
• 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

Evidence notes

The CVE record and NVD entry provide details on the vulnerability, including its description, CVSS score, and affected products. Mozilla has released advisories (MFSA2026-90, MFSA2026-92, MFSA2026-93, MFSA2026-94, MFSA2026-95, MFSA2026-96) addressing this issue.

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.