CVE-2026-110247Integer overflow in libmime buffer growth could lead to heap corruption
Updated under an hour ago ()
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It affects Mozilla Thunderbird. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- Not yet scored
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- mozilla
- NVD analysis
- Awaiting Analysis
- Record last updated
- Oct 13, 2026
- First seen by InfoSec Signals
- Oct 13, 2026
Affected products
Mozilla Thunderbird mozilla:thunderbird (from the name) | from 158 not affected | CNA record |
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=2071621
- https://www.mozilla.org/security/advisories/mfsa2026-109/
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.