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Fedora 43 ClamAV Denial of Service Patch FEDORA-2026

Linuxsecurity •LinuxSecurity Advisories • August 12, 2026

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Clam AntiVirus is an anti-virus toolkit for UNIX. The main purpose of this

software is the integration with mail servers (attachment scanning). The

package provides a flexible and scalable multi-threaded daemon, a command

line scanner, and a tool for automatic updating via Internet. The programs

are based on a shared library distributed with the Clam AntiVirus package,

which you can use with your own software. The virus database is based on

the virus database from OpenAntiVirus, but contains additional signatures

(including signatures for popular polymorphic viruses, too) and is KEPT UP

* Mon Aug 10 2026 Gwyn Ciesla - 1.4.6-1 - Update to 1.4.6 * Wed Jul 15 2026 Fedora Release Engineering - 1.4.5-3 - Rebuilt for * Fri Jul 10 2026 Jerry James - 1.4.5-2 - Remove unused ocaml BuildRequires

[ 1 ] Bug #2444609 - CVE-2026-20031 clamav: improper error handling when splitting UTF-8 strings in the HTML Cascading Style Sheets (CSS) module [epel-all] [ 2 ] Bug #2444610 - CVE-2026-20031 clamav: improper error handling when splitting UTF-8 strings in the HTML Cascading Style Sheets (CSS) module [fedora-all] [ 3 ] Bug #2496742 - CVE-2026-20216 clamav: ClamAV: Denial of Service via crafted InstallShield file [epel-all] [ 4 ] Bug #2496743 - CVE-2026-20216 clamav: ClamAV: Denial of Service via crafted InstallShield file [fedora-all] [ 5 ] Bug #2496819 - CVE-2026-20215 clamav: ClamAV: Denial of Service via crafted 7z file [epel-all] [ 6 ] Bug #2496820 - CVE-2026-2021...

This update can be installed with the "dnf" update program. Use su -c 'dnf upgrade --advisory FEDORA-2026-a9beec8485' at the command line. For more information, refer to the dnf documentation available at

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The full story

This article is one source in a clustered incident — the cluster page carries the summary, timeline and every other outlet covering it.

Denial of Service Vulnerabilities in ClamAV Affect Fedora 43 and 44 Fedora has released patches addressing multiple Denial of Service vulnerabilities in ClamAV, affecting versions 1.4.5 and 1.4.6. The vulnerabilities include CVE-2026-20031, CVE-2026-20216, and CVE-2026-20215, which can be exploited via crafted files, leading to service disruptions. The issues were reported on August 10, 2026, and are linked to improper error handling in the software's CSS module and crafted InstallShield files. Users are advised to update their systems using the 'dnf' update program. The vulnerabilities primarily impact Linux systems running Fedora 43 and 44. Immediate action is recommended to mitigate potential service outages. 2 sources 61

Extracted Entities

Attack Types (1)

DDoS

CVEs (4)

CVE-2026-20031 CVE-2026-2021 CVE-2026-20215 CVE-2026-20216