🔐 CVE Alert

CVE-2025-9187

CRITICAL 9.8

Memory safety bugs fixed in Firefox 142 and Thunderbird 142

CVSS Score
9.8
EPSS Score
0.1%
EPSS Percentile
20th

Memory safety bugs present in Firefox 141 and Thunderbird 141. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox 142 and Thunderbird 142.

Vendor mozilla
Product firefox
Ecosystems
Industries
Technology
Published Aug 19, 2025
Last Updated Apr 13, 2026
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Affected Versions

Mozilla / Firefox
All versions affected
Mozilla / Thunderbird
All versions affected

References

NVD ↗ CVE.org ↗ EPSS Data ↗
bugzilla.mozilla.org: https://bugzilla.mozilla.org/buglist.cgi?bug_id=1825621%2C1970079%2C1976736%2C1979072 mozilla.org: https://www.mozilla.org/security/advisories/mfsa2025-64/ mozilla.org: https://www.mozilla.org/security/advisories/mfsa2025-70/

Credits

Andy Leiserson, Maurice Dauer, Sebastian Hengst and the Mozilla Fuzzing Team