# CVE-2025-51846: CryptPad unbounded WebSocket frame flood

> A remote unauthenticated attacker can degrade or deny service to all users of a CryptPad instance via unbounded WebSocket frame floods.

- **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/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:** 30 Apr 2026
- **Updated:** 30 Apr 2026
- **Also known as:** GHSA-jmrh-f3j8-q3c4

## What is CVE-2025-51846?

CVE-2025-51846 is a high-severity denial of service vulnerability in CryptPad, published on 30 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

CryptPad 2025.3.1 allows unbounded WebSocket frame flood. A remote, unauthenticated attacker can significantly degrade or deny service for all users of a CryptPad instance. Fixed in 2026.2.2.

Weakness: CWE-770 (Allocation of Resources Without Limits or Throttling)

## Which versions are affected by CVE-2025-51846?

It affects 1 product.


Products: Xwiki Cryptpad.

## How do I fix CVE-2025-51846?

No fix has been published for CVE-2025-51846 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-51846 being exploited?

There is no known exploitation of CVE-2025-51846 in the wild and no public exploit code.

Public exploit code:

- Sanitized advisory for CVE-2025-51846 affecting CryptPad WebSocket handling. (github_poc): https://github.com/JohnPerifanis/cryptpad-cve-2025-51846-advisory

## Other vulnerabilities in CryptPad

- [CVE-2025-49591](https://insights.sbomify.com/CVE-2025-49591/): CryptPad 2FA Bypass Vulnerability (high 7.4)
- [CVE-2019-15302](https://insights.sbomify.com/CVE-2019-15302/): Denial of service in n/a (medium 6.5)
- [CVE-2017-1000051](https://insights.sbomify.com/CVE-2017-1000051/): Cross-site scripting in n/a (medium 6.1)
- [CVE-2025-49590](https://insights.sbomify.com/CVE-2025-49590/): CryptPad Dom-Based Cross-Site Scripting (XSS) Vulnerability (low 2.9)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-51846 and fix it if it is affected.

What it is: CVE-2025-51846 is a high-severity denial of service vulnerability in CryptPad, published on 30 Apr 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-2025-51846 in the wild and no public exploit code.

Affected product: CryptPad. 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-2025-51846/ (Markdown: https://insights.sbomify.com/CVE-2025-51846/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-51846
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-51846
- OSV: https://osv.dev/vulnerability/CVE-2025-51846

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-51846/
Summaries are generated and may contain mistakes; the official description above is the record.