CVE-2026-92042 Mozilla CVE debrief

Who should care

Defenders responsible for managing and securing Firefox, Firefox ESR, Thunderbird, and Thunderbird ESR installations should assess exposure and prioritize patching to prevent potential exploitation.

Why it matters

A race condition vulnerability in Firefox, Firefox ESR, Thunderbird, and Thunderbird ESR requires verification and patching to prevent potential exploitation.

• Verify and apply patches to prevent potential exploitation.
• Review and update inventory of affected software versions.
• Monitor for potential exploitation attempts.

Technical summary

A race condition vulnerability exists in the DOM: Content Processes component of Firefox, Firefox ESR, Thunderbird, and Thunderbird ESR. This issue was fixed in Firefox 156, Firefox ESR 153.3, Thunderbird 156, and Thunderbird 153.3. The vulnerability requires verification and patching to prevent potential exploitation. Defenders should prioritize verifying and applying patches for Firefox, Firefox ESR, Thunderbird, and Thunderbird ESR to prevent potential exploitation. The CVE record and NVD entry provide details on the vulnerability, including its CVSS score and severity.

Defensive priority

Defenders should prioritize verifying and applying patches for Firefox, Firefox ESR, Thunderbird, and Thunderbird ESR to prevent potential exploitation.

Recommended defensive actions

• Verify and apply patches for Firefox, Firefox ESR, Thunderbird, and Thunderbird ESR.
• Review and update inventory of Firefox, Firefox ESR, Thunderbird, and Thunderbird ESR installations.
• Monitor for potential exploitation attempts.
• 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 NVD entry provide details on the vulnerability, including its CVSS score and severity. Mozilla's security advisories (MFSA 2026-90, MFSA 2026-93, MFSA 2026-94, and MFSA 2026-96) offer additional information on the vulnerability and its fixes.

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.