# CVE-2026-121611: Gstreamer1-plugins-bad-free: gst-plugins-bad: use of uninitialized gsth265hrdparams in gst_h265_parse_vps() multi-hrd workaround loop

Status: published. Published: 2026-11-09. Updated: 2026-11-10.

A flaw was found in GStreamer's gst-plugins-bad package. A use of uninitialized memory vulnerability exists in the H.265 (HEVC) bitstream parser when processing Video Parameter Sets that declare more than one HRD (Hypothetical Reference Decoder) parameter set. A remote attacker could exploit this by providing a crafted H.265 media file or stream that, when processed by an application using GStreamer, causes unpredictable parser behavior and may crash the application. This can lead to a denial of service for any application using GStreamer to play back H.265 content.

## Remediation

- workaround: No mitigation is currently available that meets Red Hat Product Security's standards for usability, deployment, applicability, or stability. (source: CNA: redhat)

## Affected products and versions

- Red Hat / Red Hat Enterprise Linux 10 (gstreamer1-plugins-bad-free): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 7 (gstreamer1-plugins-bad-free): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8 (gstreamer1-plugins-bad-free): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9 (gstreamer1-plugins-bad-free): Version range not reported. Source: CNA: redhat

## Severity and prioritization

- CVSS 3.1: 6.5 (medium); CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H; source: CNA: redhat

- CVSS 3.1: 6.5 (medium); CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H; source: NVD: secalert@redhat.com

- CISA KEV: No listing in collected sources

- EPSS: 0.56% as of 2026-11-10; percentile 47.15%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-457

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://access.redhat.com/security/cve/CVE-2026-121611 (CNA: redhat; vdb-entry, x_refsource_REDHAT)

- https://bugzilla.redhat.com/show_bug.cgi?id=2565937 (CNA: redhat; issue-tracking, x_refsource_REDHAT)

- https://gitlab.freedesktop.org/gstreamer/gstreamer/-/work_items/5332 (CNA: redhat)

- https://gstreamer.freedesktop.org/security/sa-2026-0094.html (CNA: redhat)

- https://access.redhat.com/security/cve/CVE-2026-121611 (secalert@redhat.com)

- https://bugzilla.redhat.com/show_bug.cgi?id=2565937 (secalert@redhat.com)

- https://gitlab.freedesktop.org/gstreamer/gstreamer/-/work_items/5332 (secalert@redhat.com)

- https://gstreamer.freedesktop.org/security/sa-2026-0094.html (secalert@redhat.com)

## Provenance

- CNA: redhat: https://www.cve.org/CVERecord?id=CVE-2026-121611; retrieved 2026-11-10; source updated 2026-11-10

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-121611; retrieved 2026-11-09; source updated 2026-11-09

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-121611; retrieved 2026-11-10; source updated Not reported

Revision: a60d5f9e9af05b7c827aaa833cc59c18a044b9e17dac3b89375490eadc14cca4

Canonical: https://y2.dev/cve/CVE-2026-121611

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