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CVE-2026-103680

Tnef: heap buffer overflow in find_free_number() via numbered-backup suffix generation

CVSS 3.1 3.1 LOWCheck source for fixed versionsKEV status unknown
Original advisory

Historical advisory recorded 23 Oct 2026 15:48:27 UTC. Read the latest advisory.

cve-program · CVE-2026-103680

Published

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.

Read the publisher's advisory

Affected versions, risk and source history

cve-program · CVE-2026-103680

Published

Tnef: heap buffer overflow in find_free_number() via numbered-backup suffix generation

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.

Source published
1 Oct 2026 11:34:51 UTC
Source modified
1 Oct 2026 14:58:06 UTC
Saved here
23 Oct 2026 15:48:27 UTC
Source terms
CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

Source: cve-program · CVE Program Terms of Use. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

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

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Sources read 12 Nov 14:22 UTC · 274 of 275 readable · 272 fully read · documentation 469/469 current

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