# CVE-2021-47812: GravCMS 1.10.7 - Arbitrary YAML Write/Update (Unauthenticated) (2)

> Unauthenticated attackers can write arbitrary YAML and execute PHP code via the scheduler endpoint in GravCMS, leading to remote code execution.

- **Severity:** Critical 9.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 15 Jan 2026
- **Updated:** 7 Apr 2026
- **Also known as:** GHSA-474v-g7v9-75hp

## What is CVE-2021-47812?

CVE-2021-47812 is a critical missing authorization vulnerability in Getgrav Grav, published on 15 Jan 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

GravCMS 1.10.7 contains an unauthenticated vulnerability that allows remote attackers to write arbitrary YAML configuration and execute PHP code through the scheduler endpoint. Attackers can exploit the admin-nonce parameter to inject base64-encoded payloads and create malicious custom jobs with system command execution.

Weakness: CWE-862 (Missing Authorization)

## Which versions are affected by CVE-2021-47812?

It affects 1 product.


Products: Getgrav Grav.

## How do I fix CVE-2021-47812?

No fix has been published for CVE-2021-47812 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-47812 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-47812 exists.

## Other vulnerabilities in Getgrav Grav

- [CVE-2023-34251](https://insights.sbomify.com/CVE-2023-34251/): Grav Server Side Template Injection vulnerability (critical 10.0)
- [CVE-2025-46199](https://insights.sbomify.com/CVE-2025-46199/): Cross-site scripting in n/a (critical 9.8)
- [CVE-2025-66844](https://insights.sbomify.com/CVE-2025-66844/): Grav may be vulnerable to SSRF attack via Twig Templates (critical 9.1)
- [CVE-2022-2073](https://insights.sbomify.com/CVE-2022-2073/): Code Injection in getgrav/grav (critical 9.1)
- [CVE-2026-42611](https://insights.sbomify.com/CVE-2026-42611/): Grav: Stored XSS via Tag Injection (high 8.9)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-47812 and fix it if it is affected.

What it is: CVE-2021-47812 is a critical missing authorization vulnerability in Getgrav Grav, published on 15 Jan 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-47812 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-2021-47812/ (Markdown: https://insights.sbomify.com/CVE-2021-47812/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-47812
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-47812
- OSV: https://osv.dev/vulnerability/CVE-2021-47812

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-47812/
Summaries are generated and may contain mistakes; the official description above is the record.