# CVE-2026-53703: GStreamer RealMedia demuxer out-of-bounds read in MDPR chunk parsing

Source: https://junglewise.ai/threats/cve-2026-53703-gstreamer-realmedia-demuxer-out-of-bounds-read-in-mdpr-chunk  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-06-15. Updated: 2026-06-15  
License: CC BY 4.0 with a link back

CVE-2026-53703 · Severity: high · CVSS 7.1 · Published 2026-06-15

A vulnerability exists in the GStreamer RealMedia demuxer, a component used to process and play RealMedia (.rm) video and audio files. By tricking a user into opening a specially crafted malicious media file, an attacker can cause the application to crash or potentially access small amounts of sensitive information from the system's memory. This could lead to service disruptions for users or applications relying on GStreamer for media playback.

Technologies: [Gstreamer Gst-Plugins-Ugly](https://junglewise.ai/threats/technologies/gst-plugins-ugly). Vendors: [Gstreamer](https://junglewise.ai/threats/vendors/gstreamer).

## Quick answers

**Is CVE-2026-53703 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-53703 being exploited in the wild.

**How severe is CVE-2026-53703?** High severity, with a CVSS score of 7.1, published 15 June 2026.

**Which products and versions are affected?** Gstreamer Gst-Plugins-Ugly unspecified.

**Is there a fix for CVE-2026-53703?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-53703 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-53703?** Check whether you run Gstreamer Gst-Plugins-Ugly at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

An out-of-bounds read vulnerability exists in the GStreamer RealMedia demuxer (gst-plugins-ugly) within the gst_rmdemux_parse_mdpr() function. When parsing Media Properties (MDPR) chunks for audio stream header versions 4 and 5, the demuxer reads codec parameters from fixed byte offsets without verifying that the chunk size is sufficient. An attacker can provide a malformed .rm file with a truncated MDPR chunk to trigger a read beyond the buffer boundaries. This results in an application crash (DoS) or limited information disclosure if the out-of-bounds data is incorporated into stream metadata. No official patch is currently available, and upstream developers have suggested a rewrite of the rmdemux component.

## Affected products

- GStreamer gst-plugins-ugly unspecified

## Timeline

- 2026-06-10: other: Reported via PSIRTSUPT-7239 by Tianshuo Han
- 2026-06-15: advisory: NVD and Red Hat published advisory data

## References

- [https://access.redhat.com/security/cve/CVE-2026-53703](https://access.redhat.com/security/cve/CVE-2026-53703)
- [https://bugzilla.redhat.com/show_bug.cgi?id=2487613](https://bugzilla.redhat.com/show_bug.cgi?id=2487613)

## Related threats

- [GStreamer gst-plugins-ugly ASF demuxer unbounded memory allocation](https://junglewise.ai/threats/cve-2026-112214-a-flaw-was-found-in-the-gstreamer-asf-demuxer-in-gst-plugins)
- [GStreamer RealMedia demuxer out-of-bounds read in FILEINFO metadata](https://junglewise.ai/threats/cve-2026-53704-gstreamer-realmedia-demuxer-out-of-bounds-read-in-fileinfo)
- [GStreamer RealMedia Demuxer out-of-bounds write](https://junglewise.ai/threats/cve-2026-2922-gstreamer-realmedia-demuxer-out-of-bounds-write)