# CVE-2026-12891: Information disclosure in Red Hat Enterprise Linux 10

> Attackers can leak limited memory contents by crafting malicious H.266 video files processed by GStreamer applications, exposing sensitive application data.

- **Severity:** Medium 4.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 23 Jun 2026
- **Updated:** 10 Sep 2026
- **Also known as:** DEBIAN-CVE-2026-12891, ECHO-fe2f-08ad-190b, GHSA-9j3r-2vv4-g5x8, UBUNTU-CVE-2026-12891

## What is CVE-2026-12891?

CVE-2026-12891 is a medium-severity vulnerability in Gstreamer Gstreamer, published on 23 Jun 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

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 exposing sensitive information from the application's address space.

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2026-12891?

It affects 2 products.


Products: Gstreamer Gstreamer, Redhat Enterprise Linux.

## How do I fix CVE-2026-12891?

Apply the vendor's patch.

## Is CVE-2026-12891 being exploited?

There is no known exploitation of CVE-2026-12891 in the wild and no public exploit code.

## Other vulnerabilities in Gstreamer Gstreamer

- [CVE-2026-3083](https://insights.sbomify.com/CVE-2026-3083/): GStreamer rtpqdm2depay Out-Of-Bounds Write Remote Code Execution Vulnerability (high 8.8)
- [CVE-2026-3085](https://insights.sbomify.com/CVE-2026-3085/): GStreamer rtpqdm2depay Heap-based Buffer Overflow Remote Code Execution Vulnerability (high 8.8)
- [CVE-2023-37328](https://insights.sbomify.com/CVE-2023-37328/): GStreamer PGS File Parsing Heap-based Buffer Overflow Remote Code Execution Vulnerability (high 8.8)
- [CVE-2023-37329](https://insights.sbomify.com/CVE-2023-37329/): GStreamer SRT File Parsing Heap-based Buffer Overflow Remote Code Execution Vulnerability (high 8.8)
- [CVE-2023-38103](https://insights.sbomify.com/CVE-2023-38103/): GStreamer RealMedia File Parsing Integer Overflow Remote Code Execution Vulnerability (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-12891 and fix it if it is affected.

What it is: CVE-2026-12891 is a medium-severity vulnerability in Gstreamer Gstreamer, published on 23 Jun 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-12891 in the wild and no public exploit code.

Affected product: Gstreamer Gstreamer. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-12891/ (Markdown: https://insights.sbomify.com/CVE-2026-12891/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-12891
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-12891
- OSV: https://osv.dev/vulnerability/CVE-2026-12891

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-12891/
Summaries are generated and may contain mistakes; the official description above is the record.