CVE-2026-110247

Published: Oct 13, 2026Modified: Oct 20, 2026

8.4

Vector

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

Exploitability: 2.5 / Impact: 5.9

Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0 (Secondary)

Description

Several buffer-growth sites in libmime performed size arithmetic in 32-bit types without overflow checks. On a sufficiently large message the growth guard could fail open, or the buffer could be reallocated smaller than required, and a subsequent memcpy would then write attacker-controlled data across adjacent heap allocations. This vulnerability was fixed in Thunderbird 158.

Related CWEs

CWE-190

Integer Overflow or Wraparound

The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.

References (2)

https://bugzilla.mozilla.org/show_bug.cgi?id=2071621

Source: security@mozilla.org

https://www.mozilla.org/security/advisories/mfsa2026-109/

Source: security@mozilla.org

Timeline

No history available yet.