# CVE-2026-20338: ClamAV ZIP File Format Processing Memory Corruption Vulnerability

CVE-2026-20338 is fixed in 9 products on 1 platform, first by clamav 1.5.4+dfsg-0ubuntu0.22.04.1, released August 7, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-20338
- Priority: High
- CVSS: 7.5 (Important)
- EPSS: 0.0056
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Aug 7, 2026
- Weakness: Double Free
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20338

## Description

A vulnerability in the zip archive parser of ClamAV could allow an unauthenticated, remote attacker to cause a DoS condition on an affected device. This vulnerability is due to improper memory handling when processing content in zip files during scanning. An attacker could exploit this vulnerability by submitting a crafted zip file for scanning. A successful exploit could allow the attacker to cause the ClamAV scanning process to terminate as a result of a memory double-free, resulting in a DoS condition on the affected software.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | clamav Ubuntu 22.04.1 LTS (jammy) | 1.5.4+dfsg-0ubuntu0.22.04.1 | [clamav 1.5.4+dfsg-0ubuntu0.22.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-clamav-1.5.4-dfsg-0ubuntu0.22.04.1.md) | Aug 7, 2026 |
| Linux | clamav Ubuntu 24.04.5 LTS (noble) | 1.5.4+dfsg-0ubuntu0.24.04.1 | [clamav 1.5.4+dfsg-0ubuntu0.24.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-clamav-1.5.4-dfsg-0ubuntu0.24.04.1.md) | Aug 7, 2026 |
| Linux | clamav Ubuntu 26.04.1 LTS (resolute) | 1.5.4+dfsg-0ubuntu0.26.04.1 | [clamav 1.5.4+dfsg-0ubuntu0.26.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-clamav-1.5.4-dfsg-0ubuntu0.26.04.1.md) | Aug 7, 2026 |
| Linux | clamav opensuse-leap 16.0 | 1.5.4-160000.1.1 | [OPENSUSE-SU-2026:21831-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21831-1.md) | Sep 11, 2026 |
| Linux | clamav sles 15.6 | 1.5.4-150600.18.31.1 | [SUSE-SU-2026:4180-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4180-1.md) | Sep 14, 2026 |
| Linux | clamav sles 15.7 | 1.5.4-150600.18.31.1 | [SUSE-SU-2026:4180-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4180-1.md) | Sep 14, 2026 |
| Linux | clamav sles 16.0 | 1.5.4-160000.1.1 | [SUSE-SU-2026:23727-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23727-1.md) | Sep 11, 2026 |
| Linux | clamav-base Ubuntu 22.04.1 LTS (jammy) | 1.5.4+dfsg-0ubuntu0.22.04.1 | [clamav-base 1.5.4+dfsg-0ubuntu0.22.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-clamav-base-1.5.4-dfsg-0ubuntu0.22.04.1.md) | Aug 7, 2026 |
| Linux | clamav-base Ubuntu 24.04.5 LTS (noble) | 1.5.4+dfsg-0ubuntu0.24.04.1 | [clamav-base 1.5.4+dfsg-0ubuntu0.24.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-clamav-base-1.5.4-dfsg-0ubuntu0.24.04.1.md) | Aug 7, 2026 |
| Linux | clamav-base Ubuntu 26.04.1 LTS (resolute) | 1.5.4+dfsg-0ubuntu0.26.04.1 | [clamav-base 1.5.4+dfsg-0ubuntu0.26.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-clamav-base-1.5.4-dfsg-0ubuntu0.26.04.1.md) | Aug 7, 2026 |
| Linux | clamav-daemon Ubuntu 22.04.1 LTS (jammy) | 1.5.4+dfsg-0ubuntu0.22.04.1 | [clamav-daemon 1.5.4+dfsg-0ubuntu0.22.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-clamav-daemon-1.5.4-dfsg-0ubuntu0.22.04.1.md) | Aug 7, 2026 |
| Linux | clamav-daemon Ubuntu 24.04.5 LTS (noble) | 1.5.4+dfsg-0ubuntu0.24.04.1 | [clamav-daemon 1.5.4+dfsg-0ubuntu0.24.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-clamav-daemon-1.5.4-dfsg-0ubuntu0.24.04.1.md) | Aug 7, 2026 |
| Linux | clamav-daemon Ubuntu 26.04.1 LTS (resolute) | 1.5.4+dfsg-0ubuntu0.26.04.1 | [clamav-daemon 1.5.4+dfsg-0ubuntu0.26.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-clamav-daemon-1.5.4-dfsg-0ubuntu0.26.04.1.md) | Aug 7, 2026 |
| Linux | clamav-docs Ubuntu 22.04.1 LTS (jammy) | 1.5.4+dfsg-0ubuntu0.22.04.1 | [clamav-docs 1.5.4+dfsg-0ubuntu0.22.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-clamav-docs-1.5.4-dfsg-0ubuntu0.22.04.1.md) | Aug 7, 2026 |
| Linux | clamav-docs Ubuntu 24.04.5 LTS (noble) | 1.5.4+dfsg-0ubuntu0.24.04.1 | [clamav-docs 1.5.4+dfsg-0ubuntu0.24.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-clamav-docs-1.5.4-dfsg-0ubuntu0.24.04.1.md) | Aug 7, 2026 |
| Linux | clamav-docs Ubuntu 26.04.1 LTS (resolute) | 1.5.4+dfsg-0ubuntu0.26.04.1 | [clamav-docs 1.5.4+dfsg-0ubuntu0.26.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-clamav-docs-1.5.4-dfsg-0ubuntu0.26.04.1.md) | Aug 7, 2026 |
| Linux | clamav-freshclam Ubuntu 22.04.1 LTS (jammy) | 1.5.4+dfsg-0ubuntu0.22.04.1 | [clamav-freshclam 1.5.4+dfsg-0ubuntu0.22.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-clamav-freshclam-1.5.4-dfsg-0ubuntu0.22.04.1.md) | Aug 7, 2026 |
| Linux | clamav-freshclam Ubuntu 24.04.5 LTS (noble) | 1.5.4+dfsg-0ubuntu0.24.04.1 | [clamav-freshclam 1.5.4+dfsg-0ubuntu0.24.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-clamav-freshclam-1.5.4-dfsg-0ubuntu0.24.04.1.md) | Aug 7, 2026 |
| Linux | clamav-freshclam Ubuntu 26.04.1 LTS (resolute) | 1.5.4+dfsg-0ubuntu0.26.04.1 | [clamav-freshclam 1.5.4+dfsg-0ubuntu0.26.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-clamav-freshclam-1.5.4-dfsg-0ubuntu0.26.04.1.md) | Aug 7, 2026 |
| Linux | clamav-milter Ubuntu 22.04.1 LTS (jammy) | 1.5.4+dfsg-0ubuntu0.22.04.1 | [clamav-milter 1.5.4+dfsg-0ubuntu0.22.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-clamav-milter-1.5.4-dfsg-0ubuntu0.22.04.1.md) | Aug 7, 2026 |
| Linux | clamav-milter Ubuntu 24.04.5 LTS (noble) | 1.5.4+dfsg-0ubuntu0.24.04.1 | [clamav-milter 1.5.4+dfsg-0ubuntu0.24.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-clamav-milter-1.5.4-dfsg-0ubuntu0.24.04.1.md) | Aug 7, 2026 |
| Linux | clamav-milter Ubuntu 26.04.1 LTS (resolute) | 1.5.4+dfsg-0ubuntu0.26.04.1 | [clamav-milter 1.5.4+dfsg-0ubuntu0.26.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-clamav-milter-1.5.4-dfsg-0ubuntu0.26.04.1.md) | Aug 7, 2026 |
| Linux | clamav-testfiles Ubuntu 22.04.1 LTS (jammy) | 1.5.4+dfsg-0ubuntu0.22.04.1 | [clamav-testfiles 1.5.4+dfsg-0ubuntu0.22.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-clamav-testfiles-1.5.4-dfsg-0ubuntu0.22.04.1.md) | Aug 7, 2026 |
| Linux | clamav-testfiles Ubuntu 24.04.5 LTS (noble) | 1.5.4+dfsg-0ubuntu0.24.04.1 | [clamav-testfiles 1.5.4+dfsg-0ubuntu0.24.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-clamav-testfiles-1.5.4-dfsg-0ubuntu0.24.04.1.md) | Aug 7, 2026 |
| Linux | clamav-testfiles Ubuntu 26.04.1 LTS (resolute) | 1.5.4+dfsg-0ubuntu0.26.04.1 | [clamav-testfiles 1.5.4+dfsg-0ubuntu0.26.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-clamav-testfiles-1.5.4-dfsg-0ubuntu0.26.04.1.md) | Aug 7, 2026 |
| Linux | clamdscan Ubuntu 22.04.1 LTS (jammy) | 1.5.4+dfsg-0ubuntu0.22.04.1 | [clamdscan 1.5.4+dfsg-0ubuntu0.22.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-clamdscan-1.5.4-dfsg-0ubuntu0.22.04.1.md) | Aug 7, 2026 |
| Linux | clamdscan Ubuntu 24.04.5 LTS (noble) | 1.5.4+dfsg-0ubuntu0.24.04.1 | [clamdscan 1.5.4+dfsg-0ubuntu0.24.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-clamdscan-1.5.4-dfsg-0ubuntu0.24.04.1.md) | Aug 7, 2026 |
| Linux | clamdscan Ubuntu 26.04.1 LTS (resolute) | 1.5.4+dfsg-0ubuntu0.26.04.1 | [clamdscan 1.5.4+dfsg-0ubuntu0.26.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-clamdscan-1.5.4-dfsg-0ubuntu0.26.04.1.md) | Aug 7, 2026 |
| Linux | libclamav12 Ubuntu 22.04.1 LTS (jammy) | 1.5.4+dfsg-0ubuntu0.22.04.1 | [libclamav12 1.5.4+dfsg-0ubuntu0.22.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libclamav12-1.5.4-dfsg-0ubuntu0.22.04.1.md) | Aug 7, 2026 |
| Linux | libclamav12 Ubuntu 24.04.5 LTS (noble) | 1.5.4+dfsg-0ubuntu0.24.04.1 | [libclamav12 1.5.4+dfsg-0ubuntu0.24.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libclamav12-1.5.4-dfsg-0ubuntu0.24.04.1.md) | Aug 7, 2026 |
| Linux | libclamav12 Ubuntu 26.04.1 LTS (resolute) | 1.5.4+dfsg-0ubuntu0.26.04.1 | [libclamav12 1.5.4+dfsg-0ubuntu0.26.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libclamav12-1.5.4-dfsg-0ubuntu0.26.04.1.md) | Aug 7, 2026 |

---

Data as of 2026-11-08T19:12:23Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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