CVE-2026-103500: Vulnerability in Mozilla Thunderbird
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.
AI Analysis
Technical Summary
This vulnerability involves a heap buffer overflow in Mozilla Thunderbird triggered by opening an email message that is greater than or equal to 2GB in size. The flaw could lead to memory corruption. Mozilla has released fixes in Thunderbird versions 157, 140.17, and 153.4 to remediate this issue.
Potential Impact
An attacker could exploit this vulnerability by convincing a user to open a very large email message (≥2GB), potentially causing a heap buffer overflow. This may lead to application crashes or other memory corruption effects. No specific exploitation details or active exploits in the wild are reported.
Mitigation Recommendations
Users should update Mozilla Thunderbird to version 157, 140.17, 153.4, or later, where this vulnerability has been fixed. Applying these official patches fully mitigates the risk.
CVE-2026-103500: Vulnerability in Mozilla Thunderbird
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.
Affected software
Mozilla
Thunderbird
pkg:github/mozilla/thunderbirdRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability involves a heap buffer overflow in Mozilla Thunderbird triggered by opening an email message that is greater than or equal to 2GB in size. The flaw could lead to memory corruption. Mozilla has released fixes in Thunderbird versions 157, 140.17, and 153.4 to remediate this issue.
Potential Impact
An attacker could exploit this vulnerability by convincing a user to open a very large email message (≥2GB), potentially causing a heap buffer overflow. This may lead to application crashes or other memory corruption effects. No specific exploitation details or active exploits in the wild are reported.
Mitigation Recommendations
Users should update Mozilla Thunderbird to version 157, 140.17, 153.4, or later, where this vulnerability has been fixed. Applying these official patches fully mitigates the risk.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- mozilla
- Date Reserved
- 2026-09-30T17:15:06.146Z
- State
- PUBLISHED
- Vendor Advisory Urls
- [{"url":"https://www.mozilla.org/security/advisories/mfsa2026-101/","vendor":"Mozilla"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-102/","vendor":"Mozilla"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-103/","vendor":"Mozilla"}]
Threat ID: 6abe74a8a43b0b3b89bd1dca
Added to database: 10/01/2026, 14:56:40 UTC
Last enriched: 10/01/2026, 15:42:20 UTC
Last updated: 10/02/2026, 03:48:16 UTC
Views: 16
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