CVE-2026-103500

UNKNOWN 0.0

Heap buffer overflow opening large email

CVSS Score

0.0

EPSS Score

0.0%

EPSS Percentile

0th

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.

Vendor	mozilla
Product	thunderbird
Ecosystems	Browser JavaScript
Industries	Technology
Published	Sep 30, 2026
Last Updated	Sep 30, 2026

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Affected Versions

Mozilla / Thunderbird

All versions affected

References

NVD ↗ CVE.org ↗ EPSS Data ↗

bugzilla.mozilla.org: https://bugzilla.mozilla.org/show_bug.cgi?id=2070267 mozilla.org: https://www.mozilla.org/security/advisories/mfsa2026-101/ mozilla.org: https://www.mozilla.org/security/advisories/mfsa2026-102/ mozilla.org: https://www.mozilla.org/security/advisories/mfsa2026-103/

Credits

Ahmed Albalawi