CVE-2025-6436

HIGH EPSS 85.1%
Published Jun 24, 20251y ago · Modified Jun 17, 20261w ago
8.1 CVSS 3.1
High
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Published Jun 24, 2025 1y ago
Last Modified Jun 17, 2026 1w ago

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 was fixed in Firefox 140 and Thunderbird 140.

CVSS Details

Base Score
8.1
Exploitability
2.2
Impact
5.9
Vector string
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack Vector Network
Attack Complexity High
Privileges Required None
User Interaction None
Scope Unchanged
Confidentiality High
Integrity High
Availability High

Threat Intelligence

EPSS Exploit Probability
85.1% percentile
Exploit & Patch Status
No Known Exploit
No Patch Available

Weaknesses 1

CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer Memory Safety

Affected Products 2

VendorProductVersionRange
mozillafirefox* <140.0
mozillathunderbird* <140.0

References 3

  • bugzilla.mozilla.org https://bugzilla.mozilla.org/buglist.cgi?bug_id=1941377%2C1960948%2C1966187%2C1966505%2C1970764%2C1942930
    Permissions Required
  • mozilla.org https://www.mozilla.org/security/advisories/mfsa2025-51/
    Vendor Advisory
  • mozilla.org https://www.mozilla.org/security/advisories/mfsa2025-54/
    Vendor Advisory

Remediation

No remediation data recorded yet

Check vendor advisories and the NVD entry for patch availability.