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.

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Solution

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History

Thu, 01 Oct 2026 11:45:00 +0000

Type Values Removed Values Added
Description 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.
Title Tnef: heap buffer overflow in find_free_number() via numbered-backup suffix generation
Weaknesses CWE-787
References
Metrics cvssV3_1

{'score': 3.1, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:L'}


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cve-icon MITRE

Status: PUBLISHED

Assigner: fedora

Published:

Updated: 2026-10-01T11:34:51.984Z

Reserved: 2026-10-01T09:06:43.923Z

Link: CVE-2026-103680

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-10-01T12:17:15.810

Modified: 2026-10-01T13:02:09.610

Link: CVE-2026-103680

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-10-01T13:30:06Z

Weaknesses