# CVE-2026-19912: CVE-2026-19912

> Unauthenticated attackers can achieve remote code execution via unsafe deserialization and path traversal in the Kaltura HTML5 player.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 25 Aug 2026
- **Updated:** 1 Sep 2026
- **Also known as:** GHSA-537c-gp6x-jr7q

## What is CVE-2026-19912?

CVE-2026-19912 is a critical unsafe deserialization vulnerability in Kaltura HTML5 Video Player, html5 library, published on 25 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The Kaltura HTML5 player (mwEmbed / html5lib) contains an unauthenticated remote code execution vulnerability caused by unsafe data deserialization and unsanitized filesystem path construction. mwEmbedLoader.php accepts a user‑controlled ServiceUrl, whose response is passed to unserialize(), and the resulting object’s fields are written to a cache path derived from attacker‑supplied uiconf_id without proper path validation. An attacker can write arbitrary files into web‑accessible locations and achieve code execution as the webserver user. Affected versions include html5lib v2.45, v2.103 and earlier, and other v2.x releases exposing the vulnerable endpoint.

Weakness: CWE-22 (Improper Limitation of a Pathname to a Restricted Directory), CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2026-19912?


## How do I fix CVE-2026-19912?

No fix has been published for CVE-2026-19912 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-19912 being exploited?

There is no known exploitation of CVE-2026-19912 in the wild and no public exploit code.

Public exploit code:

- CVE-2026-19912, CVE-2026-19913, CVE-2026-19914 (github_poc): https://github.com/HORKimhab/CVE-2026-19912-CVE-2026-19913-CVE-2026-19914

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-19912 and fix it if it is affected.

What it is: CVE-2026-19912 is a critical unsafe deserialization vulnerability in Kaltura HTML5 Video Player, html5 library, published on 25 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-19912 in the wild and no public exploit code.

Affected product: Kaltura HTML5 Video Player, html5 library. 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-2026-19912/ (Markdown: https://insights.sbomify.com/CVE-2026-19912/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-19912
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-19912
- OSV: https://osv.dev/vulnerability/CVE-2026-19912

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-19912/
Summaries are generated and may contain mistakes; the official description above is the record.