tnef up to 1.4.18 find_free_number buffer overflow

Summaryinfo

A vulnerability described as problematic has been identified in tnef up to 1.4.18. This affects the function find_free_number. Such manipulation leads to buffer overflow. This vulnerability is traded as CVE-2026-103680. The attack may be launched remotely. There is no exploit available.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in tnef up to 1.4.18. Affected by this issue is the function find_free_number. The manipulation with an unknown input leads to a buffer overflow vulnerability. Using CWE to declare the problem leads to CWE-120. The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow. Impacted is availability. CVE summarizes:

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.

The advisory is available at access.redhat.com. This vulnerability is handled as CVE-2026-103680 since 10/01/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. Successful exploitation requires user interaction by the victim. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 10/01/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-90773). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Name

• tnef

Version

• 1.4.0
• 1.4.1
• 1.4.2
• 1.4.3
• 1.4.4
• 1.4.5
• 1.4.6
• 1.4.7
• 1.4.8
• 1.4.9
• 1.4.10
• 1.4.11
• 1.4.12
• 1.4.13
• 1.4.14
• 1.4.15
• 1.4.16
• 1.4.17
• 1.4.18

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Discussion