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VulnerabilityPublished Updated

CVE-2026-110247: libmime performed size arithmetic · Several Buffer-growth Sites

Source GCVE Database

0
Authoritative record:CVE-2026-110247· High 8.4

Not known to be exploited · CVSS 8.4 High.

Data as of 27 Oct 2026, 22:13 UTC

CVSS 3.1 base score
8.4High
How severe the flaw is on the 0–10 CVSS scale.
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 13 Oct 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

AI-suggested

This vulnerability is fixed in Thunderbird 158. Users and administrators should upgrade to Thunderbird 158 or later to remediate this issue. No additional mitigation steps are required as the fix fully addresses the vulnerability.

Description

CVE-2026-110247 is a high-severity vulnerability in Thunderbird's libmime library where size arithmetic was performed using 32-bit types without proper overflow checks. This flaw could cause heap corruption by allowing a buffer to be reallocated smaller than required, leading to attacker-controlled data overwriting adjacent heap allocations. The issue was fixed in Thunderbird version 158.

References

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