# Rack Gem Subject to Denial of Service via Hash Collisions

Advisory record · `GHSA-v6j3-7jrw-hq2p`

- **Identifiers:** `GHSA-v6j3-7jrw-hq2p` · `CVE-2011-5036`
- **State:** Confirmed
- **Severity:** No CVSS score
- **Critical:** No
- **Weakness (CWE):** [CWE-328](https://cwe.mitre.org/data/definitions/328.html) · [CWE-400](https://cwe.mitre.org/data/definitions/400.html)
- **Tags:** [Weak cryptography or TLS](https://agentprime.io/advisories/tag/weak-crypto.md) · [Denial of service](https://agentprime.io/advisories/tag/dos.md)
- **Published:** 17 May 2022
- **Updated:** 30 Nov 2024
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 17 May 2022, 04:59 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `rack` (RubyGems): affected `<1.1.3 || >=1.2.0, <1.2.5 || >=1.3.0, <1.3.6`; fixed in `1.1.3`, `1.2.5`, `1.3.6`
- `org.jruby:jruby-parent` (Maven): affected `<1.6.5.1`; fixed in `1.6.5.1`

## 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

No source has published a CVSS score for this record yet.

- **CISA KEV:** Not listed.
- **EPSS:** 0.039, the 90th percentile, on 8 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 15:12 UTC: First seen by agentprime
- 31 Oct 2026, 15:12 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-v6j3-7jrw-hq2p)

## Sources

- [GitHub Advisory Database: GHSA-v6j3-7jrw-hq2p](https://github.com/advisories/GHSA-v6j3-7jrw-hq2p)
- [OSV: GHSA-v6j3-7jrw-hq2p](https://osv.dev/vulnerability/GHSA-v6j3-7jrw-hq2p)
- <https://nvd.nist.gov/vuln/detail/CVE-2011-5036>
- <https://gist.github.com/52bbc6b9cc19ce330829>
- <https://github.com/rubysec/ruby-advisory-db/blob/master/gems/rack/CVE-2011-5036.yml>
- <https://web.archive.org/web/20120201040317/http://jruby.org/2011/12/27/jruby-1-6-5-1>
- <https://web.archive.org/web/20130213132312/http://archives.neohapsis.com/archives/bugtraq/2011-12/0181.html>
- <http://www.debian.org/security/2013/dsa-2783>
- <http://www.kb.cert.org/vuls/id/903934>
- <http://www.nruns.com/_downloads/advisory28122011.pdf>
- <http://www.ocert.org/advisories/ocert-2011-003.html>

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-v6j3-7jrw-hq2p>, 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-v6j3-7jrw-hq2p/>. Everything for agents: <https://agentprime.io/llms.txt>.