# CVE-2026-107844: Contao: Path traversal in the images controller

> Unauthenticated attackers can read arbitrary files within the project directory and disclose filesystem paths via path traversal in the images controller.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/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:** Not needed
- **Fix available:** Yes
- **Published:** 9 Oct 2026
- **Updated:** 14 Oct 2026
- **Also known as:** GHSA-mrvp-7wmx-5m4h

## What is CVE-2026-107844?

CVE-2026-107844 is a medium-severity path traversal vulnerability in contao, published on 9 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Contao is an Open Source CMS. From version 5.0.0 until 5.3.50 and 5.7.12, ImagesController joins the user-controlled {path} parameter to the configured image target directory with Path::join() but does not use Path::isBasePath() to verify that the canonical path remains inside that directory. An unauthenticated request containing encoded parent-directory segments can therefore return files under the project directory through BinaryFileResponse when their names use an extension allowed by contao.image.valid_extensions. The route can also reveal whether arbitrary paths exist, and debug responses can disclose absolute filesystem paths, but paths below the upload directory were not shown to be readable. This issue is fixed in versions 5.3.50 and 5.7.12.

Weakness: CWE-22 (Improper Limitation of a Pathname to a Restricted Directory)

## Which versions are affected by CVE-2026-107844?

4 open source packages ship an affected version, including contao/core-bundle.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `contao/core-bundle` | Packagist | From 4.1.0 | 5.3.50 |
| `contao/core-bundle` | Packagist | From 4.1.0 | 5.3.50 |
| `contao/core-bundle` | Packagist | From 5.4.0-RC1 | 5.7.12 |
| `contao/core-bundle` | Packagist | From 5.4.0-RC1 | 5.7.12 |

## How do I fix CVE-2026-107844?

Upgrade contao/core-bundle to a fixed version for your release line: 5.3.50 or 5.7.12.

## Is CVE-2026-107844 being exploited?

There is no known exploitation of CVE-2026-107844 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-107844 and fix it if it is affected.

What it is: CVE-2026-107844 is a medium-severity path traversal vulnerability in contao, published on 9 Oct 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-2026-107844 in the wild and no public exploit code.

Affected packages and fixed versions:
- contao/core-bundle (Packagist): affected from 4.1.0; fixed in 5.3.50
- contao/core-bundle (Packagist): affected from 4.1.0; fixed in 5.3.50
- contao/core-bundle (Packagist): affected from 5.4.0-RC1; fixed in 5.7.12
- contao/core-bundle (Packagist): affected from 5.4.0-RC1; fixed in 5.7.12

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-2026-107844/ (Markdown: https://insights.sbomify.com/CVE-2026-107844/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-107844
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-107844
- OSV: https://osv.dev/vulnerability/CVE-2026-107844

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-107844/
Summaries are generated and may contain mistakes; the official description above is the record.