Cisco ClamAV GPT File Format Parser buffer overflow

Summaryinfo

A vulnerability described as very critical has been identified in Cisco ClamAV. The impacted element is an unknown function of the component GPT File Format Parser. The manipulation results in buffer overflow. This vulnerability is reported as CVE-2026-20345. The attack can be launched remotely. No exploit exists.

Detailsinfo

A vulnerability was found in Cisco ClamAV (unknown version). It has been classified as very critical. Affected is an unknown code block of the component GPT File Format Parser. The manipulation with an unknown input leads to a buffer overflow vulnerability. CWE is classifying the issue as 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. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

A vulnerability in the GPT file format parser of ClamAV could allow an unauthenticated, remote attacker to cause a DoS condition or possibly other expanded impacts as a result of memory corruption on an affected device. This vulnerability is due to improper handling of an endian conversion operation, which may result in an out-of-bounds buffer write. An attacker could exploit this vulnerability by submitting a crafted GPT file to be scanned by ClamAV on an affected device. A successful exploit could allow the attacker to cause the ClamAV scanning process to terminate, resulting in a DoS condition on the affected software.

The advisory is available at sec.cloudapps.cisco.com. This vulnerability is traded as CVE-2026-20345 since 10/08/2025. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. Successful exploitation requires user interaction by the victim. The technical details are unknown and an exploit is not available. The structure of the vulnerability defines a possible price range of USD $5k-$25k at the moment (estimation calculated on 08/07/2026).

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-2026-54507). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Type

• Anti-Malware Software

Vendor

• Cisco

Name

• ClamAV

License

• free

Website

• Vendor: https://www.cisco.com/

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

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