# CVE-2026-121611: GStreamer gst-plugins-bad H.265 uninitialized memory use

Source: https://junglewise.ai/threats/cve-2026-121611-a-flaw-was-found-in-gstreamer-s-gst-plugins-bad-package-a-use-of  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-09. Updated: 2026-11-09  
License: CC BY 4.0 with a link back

CVE-2026-121611 · Severity: medium · CVSS 6.5 · Published 2026-11-09

GStreamer is a multimedia framework used by applications to play audio and video content. A vulnerability in the H.265 video codec parser allows a remote attacker to crash applications by sending a specially crafted video file with malformed codec parameters. An attacker could exploit this to cause denial of service against any application using GStreamer to play H.265 video content.

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

## Quick answers

**Is CVE-2026-121611 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-121611 being exploited in the wild.

**How severe is CVE-2026-121611?** Medium severity, with a CVSS score of 6.5, published 9 November 2026.

**Which products and versions are affected?** Gstreamer Gst-Plugins-Bad 1.16.0 through prior to 1.28.9.

**Is there a fix for CVE-2026-121611?** 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-2026-121611 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-121611?** Check whether you run Gstreamer Gst-Plugins-Bad 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

A use-of-uninitialized-memory flaw exists in the H.265 (HEVC) bitstream parser when processing Video Parameter Sets that declare multiple HRD (Hypothetical Reference Decoder) parameter sets. An attacker can trigger this by providing a crafted H.265 media file or stream processed by an application using the vulnerable library, causing unpredictable parser behavior and application crashes with no code execution possible.

## Affected products

- GStreamer gst-plugins-bad 1.16.0 through prior to 1.28.9

## Timeline

- 2026-11-09: disclosed

## References

- [https://access.redhat.com/downloads/content/package-browser/](https://access.redhat.com/downloads/content/package-browser/)
- [https://access.redhat.com/security/cve/CVE-2026-121611](https://access.redhat.com/security/cve/CVE-2026-121611)

## Related threats

- [GStreamer gst-plugins-bad out-of-bounds read in MPEG/DVD parsing](https://junglewise.ai/threats/cve-2026-125706-a-flaw-was-found-in-gstreamer-s-gst-plugins-bad-mpeg-program)
- [GStreamer gst-plugins-bad MXF plugin buffer overflow in VANC handling](https://junglewise.ai/threats/cve-2026-125703-a-flaw-was-found-in-the-gstreamer-gst-plugins-bad-mxf-plugin)
- [GStreamer MXF demuxer out-of-bounds read](https://junglewise.ai/threats/cve-2026-121601-a-flaw-was-found-in-gstreamer-s-mxf-demuxer-plugin-gst-plugins)
- [GStreamer gst-plugins-bad JPEG 2000 decimator integer overflow and division by zero](https://junglewise.ai/threats/cve-2026-121259-a-flaw-was-found-in-the-gstreamer-jpeg-2000-decimator-in-gst)
- [GStreamer gst-plugins-bad NULL pointer dereference in H.264 MVC parser](https://junglewise.ai/threats/cve-2026-119728-a-flaw-was-found-in-the-h-264-video-parser-in-gst-plugins-bad)