CVE-2025-1020

Memory safety bugs fixed in Firefox 135 and Thunderbird 135

CVSS 9.8 CRITICALEPSS 0.5%CWE-787

Vexday Risk Score

28Low

SSVC decision (CISA)

Track

No exploitation signal → monitor

CVSS 9.8EPSS 0.5%KEV nãoPoC —Nuclei —Metasploit —Patch —

Lifecycle

04 Feb 2025Published on NVD

Recommendation: Monitor — no exploitation signal at the moment.

Memory safety bugs present in Firefox 134 and Thunderbird 134. 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 135 and Thunderbird 135.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

Mozilla · Firefox Mozilla · Thunderbird

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References

https://bugzilla.mozilla.org/buglist.cgi?bug_id=1939063%2C1942169 https://www.mozilla.org/security/advisories/mfsa2025-07/https://www.mozilla.org/security/advisories/mfsa2025-11/