CVE-2026-103500

Publication date 30 September 2026

Last updated 16 October 2026

Ubuntu priority

Cvss 3 Severity Score

Description

An attacker could cause a heap buffer overflow by getting a user to open an email that is greater than or equal to 2GB in size. This vulnerability was fixed in Thunderbird 157, Thunderbird 140.17, and Thunderbird 153.4.

Status

Show unmaintained releases

Package	Ubuntu Release	Status
thunderbird	26.10 stonking	Needs evaluation
	26.04 LTS resolute	Needs evaluation
	24.04 LTS noble	Needs evaluation
	22.04 LTS jammy	Needs evaluation

How can I get the fixes?
What do statuses mean?

Severity score breakdown

CVSS version: CVSS v3.0

Base score 6.1 · Medium

Base metrics

Parameter	Value
Attack vector	Local
Attack complexity	Low
Privileges required	None
User interaction	Required
Scope	Unchanged
Confidentiality impact	None
Integrity impact	Low
Availability impact	High

Scores

Parameter	Value
Base score	6.1 · Medium
Exploitability score	-
Impact score	-

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

References

MITRE
NVD
Launchpad
Debian

Other references

https://www.cve.org/CVERecord?id=CVE-2026-103500
https://www.mozilla.org/en-US/security/advisories/mfsa2026-103/#CVE-2026-103500
https://bugzilla.mozilla.org/show_bug.cgi?id=2070267
https://www.mozilla.org/security/advisories/mfsa2026-101/
https://www.mozilla.org/security/advisories/mfsa2026-102/
https://www.mozilla.org/security/advisories/mfsa2026-103/