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CVE-2011-4815

28
FAUCET Score

CVE-2011-4815 describes a denial-of-service vulnerability in Ruby (CRuby) versions prior to 1.8.7-p357. The flaw stems from the way Ruby computes hash values, allowing attackers to trigger predictable hash collisions with crafted input, leading to high CPU consumption in applications utilizing hash tables. With a CVSS score of 7.8 (High), this vulnerability is easily exploitable over the network with low attack complexity, resulting in a complete denial of service. There is no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
<= 1.8.7-p352CPE matchmatch criteria
cpe:2.3:a:ruby-lang:ruby:*:*:*:*:*:*:*:*
1.8.7-p299CPE matchmatch criteria
cpe:2.3:a:ruby-lang:ruby:1.8.7-p299:*:*:*:*:*:*:*
1.8.7-p302CPE matchmatch criteria
cpe:2.3:a:ruby-lang:ruby:1.8.7-p302:*:*:*:*:*:*:*
1.8.7-p330CPE matchmatch criteria
cpe:2.3:a:ruby-lang:ruby:1.8.7-p330:*:*:*:*:*:*:*
1.8.7-p334CPE matchmatch criteria
cpe:2.3:a:ruby-lang:ruby:1.8.7-p334:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 2.0

7.8HIGH

AV:N/AC:L/Au:N/C:N/I:N/A:C

Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
COMPLETE
Access Vector
NETWORK
Access Complexity
LOW
Authentication
NONE
Exploitability Score
10.0
Impact Score
6.9
CvssVersion
2.0

Exploit Intelligence

EPSS Score
4.25%
Probability of exploitation in next 30 days
EPSS Percentile
90.0%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0425 is in the 82nd percentile among its peer group of 51,506 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (3)

redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 4Fixed in: ruby-0:1.8.1-18.el4
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 5Fixed in: ruby-0:1.8.5-22.el5_7.1
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 6Fixed in: ruby-0:1.8.7.352-4.el6_2
View patch

Vendor Advisories (1)

redhatCVE-2011-4815Moderate

ruby: hash table collisions CPU usage DoS (oCERT-2011-003)

Dec 28, 2011

References

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