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 and Thunderbird 153.6.
References3
Metrics
- CVSS 3.1
-
8.4
HIGH
Score source: CNA
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - EPSS — exploit probability
- 0% percentile: 8 · as of 11 November 2026
- CWE
- CWE-190
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