Description
Rack before 1.1.3, 1.2.x before 1.2.5, and 1.3.x before 1.3.6 computes hash values for form parameters without restricting the ability to trigger hash collisions predictably, which allows remote attackers to cause a denial of service (CPU consumption) by sending many crafted parameters.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | ruby-rack | 1.4.0-1 | — |
| Debian 13 | ruby-rack | 1.4.0-1 | — |
| Debian 12 | ruby-rack | 1.4.0-1 | — |
| Debian 6.0 | librack-ruby | 1.1.0-4+squeeze1 | DSA-2783-1 |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| Maven | org.jruby:jruby-parent | < 1.6.5.1 | 1.6.5.1 | GHSA-v6j3-7jrw-hq2p |
| RubyGems | rack | < 1.1.3 | 1.1.3 | GHSA-v6j3-7jrw-hq2p |
| RubyGems | rack | >= 1.2.0, < 1.2.5 | 1.2.5 | GHSA-v6j3-7jrw-hq2p |
| RubyGems | rack | >= 1.3.0, < 1.3.6 | 1.3.6 | GHSA-v6j3-7jrw-hq2p |
Advisories 1
- DSA-2783-1 librack-ruby - several Debian Security (DSA / DLA) · Mar 9, 2026
References
- http://www.nruns.com/_downloads/advisory28122011.pdf
- https://gist.github.com/52bbc6b9cc19ce330829
- VU#903934 third-party-advisory
- 20111228 n.runs-SA-2011.004 - web programming languages and platforms - DoS through hash table mailing-list
- DSA-2783 vendor-advisory
- http://www.ocert.org/advisories/ocert-2011-003.html