# CVE-2026-61457: Grav before 1.0.3 Remote Code Execution via File Upload Extension Bypass

> Attackers with media write permissions can upload malicious files using double extensions to achieve remote code execution on Grav CMS installations.

- **Severity:** Medium 5.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 15 Jul 2026
- **Updated:** 28 Jul 2026
- **Also known as:** CVE-2026-61606, GHSA-66v2-vxxf-xc3v, GHSA-7wcr-m737-mchr

## What is CVE-2026-61457?

CVE-2026-61457 is a medium-severity vulnerability in getgrav grav, published on 15 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

The Grav API plugin (getgrav/grav-plugin-api) before 1.0.3 contains a file upload extension bypass in the API media controller. HandlesMediaUploads::validateFileExtension() inspects only the final file extension via pathinfo($filename, PATHINFO_EXTENSION), so a user with api.media.write permission can upload a file with a double extension such as shell.php.jpg to bypass the dangerous extensions blocklist. The web server may then execute the file as PHP, resulting in remote code execution.

Weakness: CWE-434 (Unrestricted Upload of File with Dangerous Type)

## Which versions are affected by CVE-2026-61457?


## How do I fix CVE-2026-61457?

No fix has been published for CVE-2026-61457 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-61457 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-61457 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-61457 and fix it if it is affected.

What it is: CVE-2026-61457 is a medium-severity vulnerability in getgrav grav, published on 15 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-61457 exists.

Affected product: getgrav grav. 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-2026-61457/ (Markdown: https://insights.sbomify.com/CVE-2026-61457/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-61457
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-61457
- OSV: https://osv.dev/vulnerability/CVE-2026-61457

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-61457/
Summaries are generated and may contain mistakes; the official description above is the record.