CVE-2026-92029 Mozilla CVE debrief

Who should care

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

Why it matters

A use-after-free vulnerability in the SVG component of Firefox, Firefox ESR, and Thunderbird has been addressed. Defenders should prioritize verifying and applying patches to prevent potential exploitation.

• Verify and apply patches to prevent potential exploitation of the use-after-free vulnerability.
• Review and update inventory to ensure affected systems are identified and patched.
• Monitor for potential exploitation attempts using security monitoring tools.

Technical summary

The CVE-2026-92029 vulnerability is a use-after-free issue in the SVG component of Firefox, Firefox ESR, and Thunderbird. This vulnerability has been addressed in Firefox 156, Firefox ESR 115.41, Firefox ESR 140.16, Firefox ESR 153.3, Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.3. The vulnerability could allow attackers to execute arbitrary code, potentially leading to system compromise. Defenders should prioritize verifying and applying patches for these products to prevent potential exploitation of this use-after-free vulnerability. The vulnerability was fixed in multiple versions of Firefox, Firefox ESR, and Thunderbird, ensuring that users of these products are protected against potential abuse

Defensive priority

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

Recommended defensive actions

• Verify and apply patches for Firefox, Firefox ESR, and Thunderbird to address the use-after-free vulnerability.
• Review and update inventory to ensure affected systems are identified and patched.
• Monitor for potential exploitation attempts using security monitoring tools.
• 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.
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed.

Evidence notes

The CVE record and NVD detail page provide information on the vulnerability, including its CVSS score and severity. Mozilla security advisories (MFSA) provide additional context and mitigation guidance.

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.