CVE-2026-92067 Mozilla CVE debrief

Who should care

Defenders responsible for managing and securing Firefox, Firefox ESR, Thunderbird, and Thunderbird installations should prioritize verifying and applying patches to prevent potential exploitation of this use-after-free vulnerability.

Why it matters

CVE-2026-92067 is a high-severity use-after-free vulnerability in the Widget: Gtk component of Firefox, Firefox ESR, Thunderbird, and Thunderbird. Defenders should prioritize verifying and applying patches to prevent potential exploitation.

• Verify and apply patches to prevent potential exploitation of this use-after-free vulnerability.
• Review and update inventory of Firefox, Firefox ESR, Thunderbird, and Thunderbird installations to ensure patched versions are deployed.
• Monitor for potential exploitation attempts targeting this vulnerability.

Technical summary

The CVE-2026-92067 vulnerability involves a use-after-free issue in the Widget: Gtk component of various Mozilla products. This vulnerability has been addressed in Firefox 156, Firefox ESR 153.3, Thunderbird 156, and Thunderbird 153.3. The CVSS score for this vulnerability is 8.8, indicating a high severity level. The vulnerability could potentially be exploited by attackers, and defenders should prioritize verifying and applying patches to prevent potential exploitation. The official CVE Program record and NIST NVD detail page provide additional information on the vulnerability.

Defensive priority

Defenders should prioritize verifying and applying patches for Firefox, Firefox ESR, Thunderbird, and Thunderbird to prevent potential exploitation of this use-after-free vulnerability.

Recommended defensive actions

• Verify and apply patches for Firefox 156, Firefox ESR 153.3, Thunderbird 156, and Thunderbird 153.3.
• Review and update inventory of Firefox, Firefox ESR, Thunderbird, and Thunderbird installations to ensure patched versions are deployed.
• Monitor for potential exploitation attempts targeting this vulnerability.
• 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, including its CVSS score and severity. Mozilla has released advisories (MFSA2026-90, MFSA2026-93, MFSA2026-94, 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.