# CVE-2026-53704: gstreamer1-plugins-ugly-free: A flaw was found in GStreamer's RealMedia demuxer in the gst-plugins-ugly package

CVE-2026-53704 is fixed in 3 products on 1 platform, first by DEBIAN-CVE-2026-53704, released June 24, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-53704
- Priority: High
- CVSS: 7.1 (moderate)
- EPSS: 0.0025
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jun 12, 2026

## Description

A flaw was found in GStreamer's RealMedia demuxer in the gst-plugins-ugly package. When processing a RealMedia file containing a specially crafted FILEINFO metadata section, the demuxer parses variable-name and variable-value pairs using re_skip_pascal_string() without validating that offsets remain within the mapped buffer. Additionally, the element count controlling the parsing loop is read from attacker-controlled data without validation, which can cause an infinite loop. A crafted RealMedia file can cause the application to crash, hang, or potentially read limited adjacent memory contents.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | gst-plugins-ugly1.0 Debian 14 | 1.28.4-1 | [DEBIAN-CVE-2026-53704](https://patchblox.com/security/data/fix/linux/debian-cve-2026-53704.md) | Jun 24, 2026 |
| Linux | gstreamer1-plugins-ugly-free RHEL 10 | 1.24.11-1.el10_0.2 | [RHSA-2026:50688](https://patchblox.com/security/data/fix/linux/rhsa-2026-50688.md) | Jul 9, 2026 |
| Linux | gstreamer1-plugins-ugly-free RHEL 9 | 0:1.22.12-6.el9_8.1 | [RHSA-2026:36674](https://patchblox.com/security/data/fix/linux/rhsa-2026-36674.md) | Jul 9, 2026 |
| Linux | gstreamer1-plugins-ugly-free almalinux 10 | 1.26.7-2.el10_2.1 | [ALSA-2026:36673](https://patchblox.com/security/data/fix/linux/alsa-2026-36673.md) | Jul 8, 2026 |
| Linux | gstreamer1-plugins-ugly-free almalinux 9 | 1.22.12-6.el9_8.1 | [ALSA-2026:36674](https://patchblox.com/security/data/fix/linux/alsa-2026-36674.md) | Jul 8, 2026 |
| Linux | gstreamer1-plugins-ugly-free ol 9 | 0:1.22.12-6.el9_8.1 | [ELSA-2026-36674](https://patchblox.com/security/data/fix/linux/elsa-2026-36674.md) | Jul 8, 2026 |
| Linux | gstreamer1-plugins-ugly-free rocky 9 | 0:1.22.12-6.el9_8.1 | [RLSA-2026:36674](https://patchblox.com/security/data/fix/linux/rlsa-2026-36674.md) | Jul 10, 2026 |
| Linux | gstreamer1.0-plugins-ugly Ubuntu 18.04.6 LTS (bionic) | 1.14.5-0ubuntu1~18.04.1+esm1 | [gstreamer1.0-plugins-ugly 1.14.5-0ubuntu1~18.04.1+esm1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-gstreamer1.0-plugins-ugly-1.14.5-0ubuntu1-18.04.1-esm1.md) | Aug 9, 2026 |
| Linux | gstreamer1.0-plugins-ugly Ubuntu 20.04 LTS (focal) | 1.16.2-2ubuntu0.1~esm1 | [gstreamer1.0-plugins-ugly 1.16.2-2ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-gstreamer1.0-plugins-ugly-1.16.2-2ubuntu0.1-esm1.md) | Aug 9, 2026 |
| Linux | gstreamer1.0-plugins-ugly Ubuntu 22.04.1 LTS (jammy) | 1.20.1-1ubuntu0.1~esm1 | [gstreamer1.0-plugins-ugly 1.20.1-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-gstreamer1.0-plugins-ugly-1.20.1-1ubuntu0.1-esm1.md) | Aug 9, 2026 |
| Linux | gstreamer1.0-plugins-ugly Ubuntu 24.04.5 LTS (noble) | 1.24.1-1ubuntu0.1~esm1 | [gstreamer1.0-plugins-ugly 1.24.1-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-gstreamer1.0-plugins-ugly-1.24.1-1ubuntu0.1-esm1.md) | Aug 9, 2026 |
| Linux | gstreamer1.0-plugins-ugly Ubuntu 26.04.1 LTS (resolute) | 1.28.2-1ubuntu0.1~esm1 | [gstreamer1.0-plugins-ugly 1.28.2-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-gstreamer1.0-plugins-ugly-1.28.2-1ubuntu0.1-esm1.md) | Aug 9, 2026 |

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Data as of 2026-11-08T13:06:02Z 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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