# Rack has possible DoS Vulnerability in Multipart MIME parsing

Advisory record · `GHSA-3h57-hmj3-gj3p`

- **Identifiers:** `GHSA-3h57-hmj3-gj3p` · `CVE-2023-27530`
- **State:** Confirmed
- **Severity:** CVSS 7.5 High
- **Critical:** No
- **Weakness (CWE):** [CWE-400](https://cwe.mitre.org/data/definitions/400.html) · [CWE-770](https://cwe.mitre.org/data/definitions/770.html)
- **Tags:** [Denial of service](https://agentprime.io/advisories/tag/dos.md)
- **Published:** 8 Mar 2023
- **Updated:** 13 Feb 2025
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 8 Mar 2023, 17:20 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `rack` (RubyGems): affected `<2.0.9.3 || >=2.1.0, <2.1.4.3 || >=2.2.0, <2.2.6.3 || >=3.0.0, <3.0.4.2`; fixed in `2.0.9.3`, `2.1.4.3`, `2.2.6.3`, `3.0.4.2`

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 7.5 High, CVSS 3.1: `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`, from GitHub Advisory Database

- **CISA KEV:** Not listed.
- **EPSS:** 0.018, the 78th percentile, on 7 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

This record came from the full history of the GitHub Advisory Database, published 8 Mar 2023. New records show when each source confirmed them.

## Sources

- [GitHub Advisory Database: GHSA-3h57-hmj3-gj3p](https://github.com/advisories/GHSA-3h57-hmj3-gj3p)
- [OSV: GHSA-3h57-hmj3-gj3p](https://osv.dev/vulnerability/GHSA-3h57-hmj3-gj3p)
- <https://nvd.nist.gov/vuln/detail/CVE-2023-27530>
- <https://discuss.rubyonrails.org/t/cve-2023-27530-possible-dos-vulnerability-in-multipart-mime-parsing/82388>
- <https://github.com/rack/rack>
- <https://github.com/rubysec/ruby-advisory-db/blob/master/gems/rack/CVE-2023-27530.yml>
- <https://lists.debian.org/debian-lts-announce/2023/04/msg00017.html>
- <https://security.netapp.com/advisory/ntap-20231208-0015>
- <https://www.debian.org/security/2023/dsa-5530>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-3h57-hmj3-gj3p>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-3h57-hmj3-gj3p/>. Everything for agents: <https://agentprime.io/llms.txt>.