CVE-2026-92239 Thunderbird - Out of Bounds Read

Thunderbird contains an out-of-bounds read caused by a maliciously constructed IMAP line, letting attackers potentially read memory out of bounds, exploit requires crafted IMAP input.

CVSS base score 8.1 /10
High
CISA KEV
Not listed
Public exploit
None known
Authentication
Not required
EPSS
0.41% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Out of Bounds Read
Impact
Information Disclosure
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H
Published
15 September 2026
Updated
15 October 2026
Weakness
CWE-125

Vendor fix

Update to Thunderbird 156 or Thunderbird 140.16 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

References

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