CVE-2026-103680

A flaw was found in tnef. A heap-based buffer overflow can occur in the find_free_number() function when generating numbered backup suffixes for duplicate filenames. When numbered backups are enabled and file overwriting is disabled, an attacker can supply a specially crafted Transport Neutral Encapsulation Format (TNEF) file with an excessive number of colliding attachment filenames, causing the numeric counter to write past the allocated memory buffer. This issue may result in an application crash, leading to a Denial of Service (DoS), or potentially arbitrary code execution.

CVSS 3.1

6.5CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

EPSS

0.3% chance of exploitation in the next 30 days; higher than 24% of CVEs (scores of 2026-10-25)

CWE

CWE-787

Published

2026-10-01

Modified

2026-10-05

Record from

the NVD, synced 2026-10-19

Affected

• tnef_project:tnef

References

• https://access.redhat.com/security/cve/CVE-2026-103680
• https://bugzilla.redhat.com/show_bug.cgi?id=2544478
• https://github.com/verdammelt/tnef

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