CVE-2011-5036
Rack Gem Subject to Denial of Service via Hash Collisions
CVE-2011-5036 is a medium vulnerability (CVSS 5.0) in Rack Project Rack, published December 30, 2011. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 3.87%, the 90th percentile. Fixed in rack 1.1.3.
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.
Exploit likelihood
What each source reports
NVD Score used
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.
- Record
CVE-2011-5036- CVSS 2.0
- 5.0 Medium
AV:N/AC:L/Au:N/C:N/I:N/A:P - Weakness
- CWE-310
- Updated
- 2026-11-02
CVE List No score
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.
- Record
CVE-2011-5036- Updated
- 2026-11-02
EUVDEUVD-2022-5298 No score
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.
- Record
EUVD-2022-5298- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-v6j3-7jrw-hq2p No score
Rack Gem Subject to Denial of Service via Hash Collisions
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.
- Record
GHSA-v6j3-7jrw-hq2p- Weakness
- CWE-328, CWE-400
- Updated
- 2026-11-02
OSV No score
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.
- Record
CVE-2011-5036- Updated
- 2026-11-02
OSVDEBIAN-CVE-2011-5036 No score
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.
- Record
DEBIAN-CVE-2011-5036- Updated
- 2026-11-02
OSVGHSA-v6j3-7jrw-hq2p No score
Rack Gem Subject to Denial of Service via Hash Collisions
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.
- Record
GHSA-v6j3-7jrw-hq2p- Weakness
- CWE-328, CWE-400
- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
rackRubyGems |
before 1.1.3 | 1.1.3 |
rackRubyGems |
1.2.0 up to 1.2.5 | 1.2.5 |
rackRubyGems |
1.3.0 up to 1.3.6 | 1.3.6 |
org.jruby:jruby-parentMaven |
before 1.6.5.1 | 1.6.5.1 |
ruby-rackDebian:12 |
before 1.4.0-1 | 1.4.0-1 |
ruby-rackDebian:13 |
before 1.4.0-1 | 1.4.0-1 |
ruby-rackDebian:14 |
before 1.4.0-1 | 1.4.0-1 |
librack-rubyDebian:6.0 |
before 1.1.0-4+squeeze1, plus listed versions 1.1.0-4 |
1.1.0-4+squeeze1 |
rackRubyGems |
before 1.1.3, plus listed versions 0.1.00.2.00.3.00.4.00.9.0 Show 7 moreShow less0.9.11.0.01.0.11.1.01.1.11.1.1.pre1.1.2 |
1.1.3 |
rackRubyGems |
1.2.0 up to 1.2.5, plus listed versions 1.2.11.2.21.2.31.2.4 |
1.2.5 |
rackRubyGems |
1.3.0 up to 1.3.6, plus listed versions 1.3.11.3.21.3.31.3.41.3.5 |
1.3.6 |
History
| When | Changed | Sources |
|---|---|---|
| 2026-11-03 | aliases | EUVD |
| 2026-11-02 | created | CVE List, GitHub Advisories, NVD, OSV |
References
nruns.com/_downloads/advisory28122011.pdf
gist.github.com/52bbc6b9cc19ce330829
kb.cert.org/vuls/id/903934
archives.neohapsis.com/archives/bugtraq/2011-12/0181.html
debian.org/security/2013/dsa-2783
ocert.org/advisories/ocert-2011-003.html
Show 6 moreShow less
nvd.nist.gov/vuln/detail/CVE-2011-5036
web.archive.org/web/20120201040317/http://jruby.org/2011/12/27/jruby-1-6-5-1
github.com/rubysec/ruby-advisory-db/blob/master/gems/rack/CVE-2011-5036.yml
security-tracker.debian.org/tracker/CVE-2011-5036