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CVE-2025-20260: Remote Code Execution or Denial-of-Service via buffer overflow write in PDF parser #4512

@SergejDurov1987

Description

@SergejDurov1987

📝 Preliminary Checks

  • I tried searching for an existing issue and followed the debugging docs advice, but still need assistance.

👀 What Happened?

CVE-2025-20260 is a buffer overflow write vulnerability located in ClamAV's PDF file parser module. It can lead to remote code execution (RCE) or denial-of-service (DoS) on affected systems.

This vulnerability is triggered only if:

max_file_size scan limit is set to ≥ 1024MB

max_scan_size scan limit is set to ≥ 1025MB

These settings might be configured by users handling large attachments or high-volume mail servers.

Please ensure that the ClamAV version used in docker-mailserver is updated to 1.4.3 (or 1.0.9 for LTS users) in the next patch release.
Additionally, a warning in the documentation about the large scan/file size limit thresholds might help reduce exposure.

👟 Reproduction Steps

No response

🐋 DMS Version

v15.0.2

💻 Operating System and Architecture

unrelated

⚙️ Container configuration files

📜 Relevant log output


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area/documentationarea/securitykind/updateUpdate an existing feature, configuration file or the documentationkind/upstreamRelated to, or resolved by, an upstream project - Not resolvable within DMSpriority/highservice/security/clamavstale-bot/ignoreIndicates that this issue / PR shall not be closed by our stale-checking CI

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