CVE-2026-103500
mediumAn 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.
Vendor / product: 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.
CVSS
6.1
6.1 (CVSS v3.1)
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:H Severity source: NVD CVSS v3.1 (nvd@nist.gov)
Timeline (UTC)
Published: 2026-09-30 18:18
Modified: 2026-10-16 19:17
NVD status: Modified
Last synced 2 days ago
Verified against the source API 2026-10-27 06:56 UTC
Exploitation
Not listed in CISA KEV (as of last catalog sync)
Absence from KEV does not mean a CVE is not exploited. Exploitation status: unknown (no authoritative evidence in our sources).
Affected products
mozilla / thunderbird <140.17.0, ≥141.0 <153.4.0, ≥154.0 <157.0
Weakness classification (CWE)
Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.
Mitigation & advisories
Vendor advisory: 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/
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=2070267 security@mozilla.org
- https://www.mozilla.org/security/advisories/mfsa2026-101/ security@mozilla.org
- https://www.mozilla.org/security/advisories/mfsa2026-102/ security@mozilla.org
- https://www.mozilla.org/security/advisories/mfsa2026-103/ security@mozilla.org
Data sources
NVD CVE API 2.0 — fetched 2026-10-27 06:56 UTC · record ↗