by Kastro
Paper/Archive/CVE-2025-1020

CVE-2025-1020

Mozilla Firefox — Memory safety bugs fixed in Firefox 135 and Thunderbird 135

EPSS 0.5%CVSS 9.8
critical.is priorityof 100
39
CVSS 9.8 (ADP, NVD agree)9.8 / 10 × 3029.4Not in CISA KEV+300.0EPSS percentile 45.3.453 × 209.1No public exploit+100.0SSVC exploitation: none+100.0
Description · from the CVE record

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.

Affected

ProductAffectedFixed inSource
Firefoxsee advisory135CNA
Thunderbirdsee advisory135CNA

Scores by source

CISA ADP9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CISA ADPSSVCExploitation: none · Automatable: no · Technical impact: partial

References

refbugzilla.mozilla.org/buglist.cgi?bug_id=1939063%2C1942169refmozilla.org/security/advisories/mfsa2025-07refmozilla.org/security/advisories/mfsa2025-11