# CVE-2021-32763: Regular Expression Denial of Service in OpenProject forum messages

> An attacker can cause a denial of service in OpenProject forums by submitting messages with unterminated pre tags that trigger excessive regex backtracking.

- **Severity:** Medium 4.3 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L`)
- **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:** 20 Jul 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-qqvp-j6gm-q56f

## What is CVE-2021-32763?

CVE-2021-32763 is a medium-severity denial of service vulnerability in opf openproject, published on 20 Jul 2021. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

OpenProject is open-source, web-based project management software. In versions prior to 11.3.3, the `MessagesController` class of OpenProject has a `quote` method that implements the logic behind the Quote button in the discussion forums, and it uses a regex to strip `<pre>` tags from the message being quoted. The `(.|\s)` part can match a space character in two ways, so an unterminated `<pre>` tag containing `n` spaces causes Ruby's regex engine to backtrack to try 2<sup>n</sup> states in the NFA. This will result in a Regular Expression Denial of Service. The issue is fixed in OpenProject 11.3.3. As a workaround, one may install the patch manually.

Weakness: CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2021-32763?

It affects 1 product.


Products: Openproject Openproject.

## How do I fix CVE-2021-32763?

No fix has been published for CVE-2021-32763 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-32763 being exploited?

There is no known exploitation of CVE-2021-32763 in the wild and no public exploit code.

## Other vulnerabilities in opf openproject

- [CVE-2026-34717](https://insights.sbomify.com/CVE-2026-34717/): OpenProject: SQL Injection in Cost Reporting =n Operator via parse_number_string (critical 9.9)
- [CVE-2026-25763](https://insights.sbomify.com/CVE-2026-25763/): Command Injection on OpenProject repositories leads to Remote Code Execution (critical 9.4)
- [CVE-2026-24685](https://insights.sbomify.com/CVE-2026-24685/): OpenProject has Argument Injection on Repository module that allows Arbitrary File Write (critical 9.4)
- [CVE-2026-32698](https://insights.sbomify.com/CVE-2026-32698/): OpenProject has a SQL Injection via Custom Field Name that can be chained to Remote Code Execution (critical 9.1)
- [CVE-2026-32703](https://insights.sbomify.com/CVE-2026-32703/): OpenProject's repository files are served with the MIME type allowing them to be used to bypass Content Security Policy (critical 9.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-32763 and fix it if it is affected.

What it is: CVE-2021-32763 is a medium-severity denial of service vulnerability in opf openproject, published on 20 Jul 2021. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-32763 in the wild and no public exploit code.

Affected product: opf openproject. 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-2021-32763/ (Markdown: https://insights.sbomify.com/CVE-2021-32763/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-32763
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-32763
- OSV: https://osv.dev/vulnerability/CVE-2021-32763

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From sbomify Insights: https://insights.sbomify.com/CVE-2021-32763/
Summaries are generated and may contain mistakes; the official description above is the record.