CVE Watchtower

CVE-2025-20260Clamav Clamav Heap-based Buffer Overflow

NVDCVSS scored by psirt@cisco.com

Vulnerability Summary

A vulnerability in the PDF scanning processes of ClamAV could allow an unauthenticated, remote attacker to cause a buffer overflow condition, cause a denial of service (DoS) condition, or execute arbitrary code on an affected device.

This vulnerability exists because memory buffers are allocated incorrectly when PDF files are processed. An attacker could exploit this vulnerability by submitting a crafted PDF file to be scanned by ClamAV on an affected device. A successful exploit could allow the attacker to trigger a buffer overflow, likely resulting in the termination of the ClamAV scanning process and a DoS condition on the affected software. Although unproven, there is also a possibility that an attacker could leverage the buffer overflow to execute arbitrary code with the privileges of the ClamAV process.
Severity Level
CRITICAL(9.8)
Published Date
Jun 18, 2025
Last Modified
Aug 11, 2025
Exploitation Status
No confirmed exploitation yet
Root Weakness (CWE)
The buffer being overwritten is allocated in the heap portion of memory.
CVSS v3.1 Base Metrics — Score 9.8 (CRITICAL)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh

Affected & Patched Versions

Affected Versions
  • Clamav Clamav < 1.0.9
  • Clamav Clamav >= 1.2.0 and < 1.4.3
Patched Versions
  • Clamav Clamav 1.0.9
  • Clamav Clamav 1.4.3

What to do

Plan remediation soon. No exploitation is confirmed yet, but the severity is critical.

  1. Check whether you run Clamav Clamav and which version.
  2. Update to a patched version listed above, then confirm the new version.

Timeline

  • Jun 18, 2025Published
  • Aug 11, 2025Record last modified

Score, severity and exploitation changes are tracked from the day Watchtower started logging them.

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Data last checked: Nov 13, 2026 11:13 (site time)