Valerie Snyder 8dd6e3cea9 Run metadata preclass scans before final verdict
Metadata preclass bytecodes ran after cli_magic_scan() finalized
the layer verdict. Evidence added by those hooks, or by the
legacy metadata JSON scan, could miss the root-layer verdict
update and clean-cache decision.

Move root metadata preclass work into cli_magic_scan() for the
root layer, before verdict finalization. Keep final metadata
serialization in scan_common(), preserve legacy RootFileType
handling, log long JSON strings in chunks, and normalize CL_BREAK
from the preclass hook to a successful control result.

Run post-scan callbacks only after the metadata preclass work has
updated the layer verdict. Reconcile the verdict and status again
after callbacks, because either callback API can add evidence or
trust the current layer.

Derive non-trusted layer verdicts from current evidence so removed
indicators do not leave stale non-clean verdicts behind.

Gate clean-cache insertion on a successful status so terminal scan
errors are not cached as clean.

CLAM-2991
2026-05-14 14:27:29 -04:00
2025-08-12 13:03:48 -04:00

ClamAV

Maeve, the ClamAV mascot

ClamAV® is an open source antivirus engine for detecting trojans, viruses, malware & other malicious threats.

Documentation & FAQ

ClamAV documentation is hosted at docs.clamav.net. The source archive for each release also includes a copy of the documentation for offline reading.

You can contribute to the documentation by submitting improvements to Cisco-Talos/clamav-documentation

ClamAV News

For information about the features in this and prior releases, read the news.

Catch up on the latest about ClamAV by reading our blog and follow us on Twitter @clamav.

ClamAV Signatures

Anyone can learn to read and write ClamAV signatures. To get started, see our signature writing manual.

Installation Instructions

Using Docker

ClamAV can be run using Docker. For details, visit to the online manual under "Docker" and check out our images on Docker Hub.

Using a Package Manager

For help installing from a package manager, refer to the online manual under "Packages".

Using an Installer

The following install packages are available for download from clamav.net/downloads:

  • Linux - Debian and RPM packages for x86_64 and i686. New in v0.104.
  • macOS - PKG installer for x86_64 and arm64 (universal). New in v0.104.
  • Windows - MSI installers and portable ZIP packages for win32 and x64.

To learn how to use these packages, refer to the online manual under "Installing".

Build from Source

For step-by-step instructions, refer to the online manual:

The source archive for each release includes a copy of the documentation for offline reading.

A reference with all of the available build options can be found in the INSTALL.md file.

You can find additional advice for developers in the online manual under "For Developers".

Upgrading from a previous version

Visit the FAQ for tips on how to upgrade from a previous version.

Join the ClamAV Community

The best way to get in touch with the ClamAV community is to join our mailing lists.

You can also join the community on our ClamAV Discord chat server.

Want to make a contribution?

The ClamAV development team welcomes code contributions, improvements to our documentation, and also bug reports.

Thanks for joining us!

Licensing

ClamAV is licensed for public/open source use under the GNU General Public License, Version 2 (GPLv2).

See COPYING.txt for a copy of the license.

3rd Party Code

ClamAV contains a number of components that include code copied in part or in whole from 3rd party projects and whose code is not owned by Cisco and which are licensed differently than ClamAV. These include:

  • Yara: Apache 2.0 license
    • Yara has since switched to the BSD 3-Clause License; Our source is out-of-date and needs to be updated.
  • 7z / lzma: public domain
  • libclamav's NSIS/NulSoft parser includes:
    • zlib: permissive free software license
    • bzip2 / libbzip2: BSD-like license
  • OpenBSD's libc/regex: BSD license
  • file: BSD license
  • str.c: Contains BSD licensed modified-implementations of strtol(), stroul() functions, Copyright (c) 1990 The Regents of the University of California.
  • pngcheck (png.c): MIT/X11-style license
  • getopt.c: MIT license
  • Curl: license inspired by MIT/X, but not identical
  • libmspack: LGPL license
  • UnRAR (libclamunrar): a non-free/restricted open source license
    • Note: The UnRAR license is incompatible with GPLv2 because it contains a clause that prohibits reverse engineering a RAR compression algorithm from the UnRAR decompression code. For this reason, libclamunrar/libclamunrar_iface is not linked at all with libclamav. It is instead loaded at run-time. If it fails to load, ClamAV will continue running without RAR support.

See the COPYING directory for a copy of the 3rd party project licenses.

Acknowledgements

Credit for contributions to each release can be found in the News.

ClamAV is brought to you by the ClamAV Team

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