# CVE-2021-25976: Piranha CMS - Site-wide Cross-Site Request Forgery (CSRF)

> Attackers can force authenticated users to perform unauthorized actions like deleting users or editing posts in Piranha CMS.

- **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 16 Nov 2021
- **Updated:** 30 Apr 2025
- **Also known as:** GHSA-ppq7-88c7-q879

## What is CVE-2021-25976?

CVE-2021-25976 is a high-severity vulnerability in PiranhaCMS Piranha, published on 16 Nov 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

In PiranhaCMS, versions 4.0.0-alpha1 to 9.2.0 are vulnerable to cross-site request forgery (CSRF) when performing various actions supported by the management system, such as deleting a user, deleting a role, editing a post, deleting a media folder etc., when an ID is known.

Weakness: CWE-352 (Cross-Site Request Forgery)

## Which versions are affected by CVE-2021-25976?

2 open source packages ship an affected version, including Piranha. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `Piranha` | NuGet | From 4.0.0-alpha1 | 10.0-alpha1 |
| `Piranha` | NuGet | From 4.0.0-alpha1 | 10.0-alpha1 |

Products: Dotnetfoundation Piranha Cms.

## How do I fix CVE-2021-25976?

Upgrade Piranha to 10.0-alpha1 or later.

## Is CVE-2021-25976 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-25976 exists.

## Other vulnerabilities in PiranhaCMS Piranha

- [CVE-2025-57692](https://insights.sbomify.com/CVE-2025-57692/): PiranhaCMS stored XSS (medium 6.8)
- [CVE-2025-67290](https://insights.sbomify.com/CVE-2025-67290/): Piranha has stored cross-site scripting (XSS) vulnerability (medium 6.1)
- [CVE-2025-67291](https://insights.sbomify.com/CVE-2025-67291/): Piranha has stored cross-site scripting (XSS) vulnerability (medium 6.1)
- [CVE-2025-61413](https://insights.sbomify.com/CVE-2025-61413/): Piranha CMS vulnerable to stored cross-site scripting (XSS) (medium 6.1)
- [CVE-2021-25977](https://insights.sbomify.com/CVE-2021-25977/): Piranha CMS - Stored XSS in Page Title (medium 5.4)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-25976 and fix it if it is affected.

What it is: CVE-2021-25976 is a high-severity vulnerability in PiranhaCMS Piranha, published on 16 Nov 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-25976 exists.

Affected packages and fixed versions:
- Piranha (NuGet): affected from 4.0.0-alpha1; fixed in 10.0-alpha1
- Piranha (NuGet): affected from 4.0.0-alpha1; fixed in 10.0-alpha1

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-2021-25976/ (Markdown: https://insights.sbomify.com/CVE-2021-25976/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-25976
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-25976
- OSV: https://osv.dev/vulnerability/CVE-2021-25976

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-25976/
Summaries are generated and may contain mistakes; the official description above is the record.