VulnerabilityModified
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.
MEDIUM 6.1EPSS 0.28%
Does this matter?
Lower severity and a low EPSS score (0.28%). Track it; it rarely justifies an emergency change on its own.
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.
- CVSS 3.1
- 6.1 MEDIUMCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:H
- EPSS
- 0.28% probability · 20th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-787, CWE-122
- Affected
- mozilla/thunderbird
- Source
- security@mozilla.org
EPSS moved from 0.2% on 1 October 2026 to 0.3% on 27 October 2026.
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=2070267Permissions 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
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.