CVE-2026-103500

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.

CVSS v3 6.1 MEDIUM

6.1^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 1.8 / Impact : 4.2

Attack Vector LOCAL

Attack Complexity LOW

Privileges Required NONE

User Interaction REQUIRED

Confidentiality Impact NONE

Integrity Impact LOW

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://bugzilla.mozilla.org/show_bug.cgi?id=2070267	Permissions Required
https://www.mozilla.org/security/advisories/mfsa2026-101/	Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-102/	Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-103/	Vendor Advisory

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:mozilla:thunderbird::::::::
	cpe:2.3:a:mozilla:thunderbird::::::::
	cpe:2.3:a:mozilla:thunderbird::::::::

History

16 Oct 2026, 19:17

Type	Values Removed	Values Added
CWE		CWE-122

15 Oct 2026, 15:03

Type	Values Removed	Values Added
CPE		cpe:2.3:a:mozilla:thunderbird::::::::
References	~~() https://bugzilla.mozilla.org/show_bug.cgi?id=2070267 -~~	() https://bugzilla.mozilla.org/show_bug.cgi?id=2070267 - Permissions Required
References	~~() https://www.mozilla.org/security/advisories/mfsa2026-101/ -~~	() https://www.mozilla.org/security/advisories/mfsa2026-101/ - Vendor Advisory
References	~~() https://www.mozilla.org/security/advisories/mfsa2026-102/ -~~	() https://www.mozilla.org/security/advisories/mfsa2026-102/ - Vendor Advisory
References	~~() https://www.mozilla.org/security/advisories/mfsa2026-103/ -~~	() https://www.mozilla.org/security/advisories/mfsa2026-103/ - Vendor Advisory
CVSS	v2 : ~~unknown~~ v3 : ~~unknown~~	v2 : unknown v3 : 6.1
CWE		CWE-787
First Time		Mozilla thunderbird Mozilla

30 Sep 2026, 18:18

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-09-30 18:18

Updated : 2026-10-16 19:17

NVD link : CVE-2026-103500

Mitre link : CVE-2026-103500

CVE.ORG link : CVE-2026-103500

JSON object : View

Products Affected

mozilla

thunderbird

CWE

CWE-787

Out-of-bounds Write

CWE-122

Heap-based Buffer Overflow

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