# CVE-2026-125040: Gst-plugins-base: gst-plugins-base: quadratic regex processing in srt/webvtt subtitle parser causes denial of service


- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 9 Nov 2026
- **Updated:** 10 Nov 2026
- **Also known as:** DEBIAN-CVE-2026-125040, ECHO-9380-f63c-93b0, GHSA-432v-qrx4-8j6c, UBUNTU-CVE-2026-125040

## What is CVE-2026-125040?

CVE-2026-125040 is a medium-severity vulnerability in Red Hat Enterprise Linux 10, published on 9 Nov 2026. 

### Official description

A flaw was found in the SRT and WebVTT subtitle parser in GStreamer's gst-plugins-base. While sanitizing inline subtitle markup, the parser repeatedly searches the remaining text with unanchored regular expressions. A crafted subtitle cue with a long line of unmatched markup-like text can force quadratic CPU use and make a GStreamer-based application unresponsive.

Weakness: CWE-1333 (Inefficient Regular Expression Complexity)

## Which versions are affected by CVE-2026-125040?


## How do I fix CVE-2026-125040?

Upgrade to a fixed version.

## Is CVE-2026-125040 being exploited?

There is no known exploitation of CVE-2026-125040 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-125040 and fix it if it is affected.

What it is: CVE-2026-125040 is a medium-severity vulnerability in Red Hat Enterprise Linux 10, published on 9 Nov 2026. 
Exploitation: There is no known exploitation of CVE-2026-125040 in the wild and no public exploit code.

Affected product: Red Hat Enterprise Linux 10. 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-2026-125040/ (Markdown: https://insights.sbomify.com/CVE-2026-125040/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-125040
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-125040
- OSV: https://osv.dev/vulnerability/CVE-2026-125040

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-125040/
Summaries are generated and may contain mistakes; the official description above is the record.