#VU111270 Out-of-bounds write in ClamAV - CVE-2025-20260

Vulnerability identifier: #VU111270

Vulnerability risk: Critical

CVSSv4.0: 8.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Red]

CVE-ID: CVE-2025-20260

CWE-ID: CWE-787

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
ClamAV
Client/Desktop applications / Antivirus software/Personal firewalls

Vendor: ClamAV

Description

The vulnerability allows a remote attacker to compromise vulnerable system.

The vulnerability exists due to a boundary error when processing PDF files. A remote attacker can pass a specially crafted PDF file to the application, trigger an out-of-bounds write and execute arbitrary code on the target system.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

ClamAV: 1.0.0, 1.0.1, 1.0.2, 1.0.3, 1.0.4, 1.0.5, 1.0.6, 1.0.7, 1.0.8, 1.1.0, 1.1.1, 1.1.2, 1.1.3, 1.2.0, 1.2.1, 1.2.2, 1.2.3, 1.3.0, 1.3.1, 1.3.2, 1.4.0, 1.4.1, 1.4.2

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External links
https://blog.clamav.net/2025/06/clamav-143-and-109-security-patch.html

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.