CVE-2026-12891: A flaw was found in the GStreamer gst-plugins-bad package

Routine

MEDIUM 4.3WATCHLISTMITIGATEMITIGATE

CVE-2026-12891 is a medium-severity flaw (CVSS 4.3) affecting gstreamer, enterprise linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A flaw was found in the GStreamer gst-plugins-bad package. When processing a malformed H.266/VVC video stream with a crafted aspect ratio indicator value, the H.266 parser performs an out-of-bounds read of up to 8 bytes from adjacent memory. This flaw allows an attacker to craft a malicious H.266 video file or stream that, when processed by a GStreamer-based application, could leak limited memory contents through video metadata, potentially expos

Why this priority

On your watchlist

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	4.3 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.4% (top 67%)
CISA exploited list	No
Weakness	CWE-125
Published	2026-06-23
Last modified	2026-07-01

Publisher (CNA): Red Hat, Inc. · Vendor: gstreamer · redhat

Last updated 2026-07-01 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-06-23 21:16 UTCPublished CVE record published
2026-07-01 18:02 UTCUpdated Record last modified

gstreamer gstreamer MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy gstreamer || rpm -q gstreamer || gstreamer --version

No fixed or unaffected release known

Apply the vendor mitigation from the advisory, disable the affected feature, or restrict network access.

redhat enterprise linux MITIGATE

Affected: 8.0 · 9.0 · 10.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 8.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-12891?

gstreamer: mitigate or apply the listed mitigation; enterprise linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2026-12891 being exploited?

CVE-2026-12891 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-12891 affect?

CVE-2026-12891 affects gstreamer, enterprise linux. Severity is medium (CVSS 4.3). A flaw was found in the GStreamer gst-plugins-bad package. When processing a malformed H.266/VVC video stream with a crafted aspect ratio indicator value, the H.266 parser performs an out-of-bounds read of up to 8 bytes from adjacent memory

How urgent is CVE-2026-12891?

Priority 28/100. On your watchlist

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CVE-2026-18298 HIGH 7.8 UPGRADE GStreamer PNG File Parsing Heap-based Buffer Overflow Remote Code Execution Vulnerability
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References

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