# CVE-2026-124881

Use-after-free in Firefox/Thunderbird CSS parsing enabling remote code execution

- Page: https://www.vulneraibility.com/cve/CVE-2026-124881
- CVSS: 8.8
- Known exploited: not in CISA KEV as of our last sync
- CISA SSVC: exploitation none, automatable no, technical impact total (assessed 2026-11-10)
- Weakness: CWE-416
- Published: 2026-11-10

## Affected

- Firefox 160
- Firefox ESR 115.45
- Firefox ESR 153.7
- Thunderbird 160
- Thunderbird 153.7

## Impact

Remote code execution via crafted CSS (use-after-free) in browser process; can lead to code execution, data theft, or persistence.

## Action

Immediate action required

## Recommendation

Update to the fixed Firefox/Thunderbird versions immediately

## References

- [other] https://bugzilla.mozilla.org/show_bug.cgi?id=2081980
- [other] https://www.mozilla.org/security/advisories/mfsa2026-125/
- [other] https://www.mozilla.org/security/advisories/mfsa2026-126/
- [other] https://www.mozilla.org/security/advisories/mfsa2026-127/
- [other] https://www.mozilla.org/security/advisories/mfsa2026-128/
- [other] https://www.mozilla.org/security/advisories/mfsa2026-129/

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Summary, impact and action are written by the vulneraibility.com AI analysis pipeline from the CVE record, NVD, CISA and FIRST data; verify against the references.