CVE-2025-6436

high

Description

Memory safety bugs present in Firefox 139 and Thunderbird 139. 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 affects Firefox < 140 and Thunderbird < 140.

References

https://www.mozilla.org/security/advisories/mfsa2025-54/

https://www.mozilla.org/security/advisories/mfsa2025-51/

https://bugzilla.mozilla.org/buglist.cgi?bug_id=1941377%2C1960948%2C1966187%2C1966505%2C1970764

Details

Source: Mitre, NVD

Published: 2025-06-24

Updated: 2025-07-14

Risk Information

CVSS v2

Base Score: 6.1

Vector: CVSS2#AV:N/AC:H/Au:N/C:N/I:P/A:C

Severity: Medium

CVSS v3

Base Score: 8.1

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

Severity: High

EPSS

EPSS: 0.0004