CVE-2011-3186

CVE-2011-3186 is a medium-severity vulnerability in Rubyonrails Rails with a CVSS 2.0 base score of 4.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-94.

Key facts

• Severity: Medium (CVSS 2.0 base score 4.3)
• EPSS exploit prediction: 2% (75th percentile)
• Actively exploited: Not listed in CISA KEV
• Weakness: CWE-94
• Affected product: Rubyonrails Rails
• Published: 2011-08-29
• Last modified: 2026-06-16

Description

CRLF injection vulnerability in actionpack/lib/action_controller/response.rb in Ruby on Rails 2.3.x before 2.3.13 allows remote attackers to inject arbitrary HTTP headers and conduct HTTP response splitting attacks via the Content-Type header.

Frequently asked questions

What is CVE-2011-3186?

CRLF injection vulnerability in actionpack/lib/action_controller/response.rb in Ruby on Rails 2.3.x before 2.3.13 allows remote attackers to inject arbitrary HTTP headers and conduct HTTP response splitting attacks via the Content-Type header.

How severe is CVE-2011-3186?

CVE-2011-3186 has a CVSS 2.0 base score of 4.3, rated medium severity.

Is CVE-2011-3186 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (75th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2011-3186?

CVE-2011-3186 primarily affects Rubyonrails Rails. In total, 7 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2011-3186?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2011-3186 published?

CVE-2011-3186 was published on 2011-08-29 and last updated on 2026-06-16.

References

• http://groups.google.com/group/rubyonrails-security/msg/bbe342e43abaa78c?dmode=source&output=gplain
• http://lists.fedoraproject.org/pipermail/package-announce/2011-September/065137.html
• http://secunia.com/advisories/45921
• http://www.debian.org/security/2011/dsa-2301
• http://www.openwall.com/lists/oss-security/2011/08/17/1
• http://www.openwall.com/lists/oss-security/2011/08/19/11
• http://www.openwall.com/lists/oss-security/2011/08/20/1
• http://www.openwall.com/lists/oss-security/2011/08/22/13
• http://www.openwall.com/lists/oss-security/2011/08/22/14
• http://www.openwall.com/lists/oss-security/2011/08/22/5
• https://bugzilla.redhat.com/show_bug.cgi?id=732156
• https://github.com/rails/rails/commit/11dafeaa7533be26441a63618be93a03869c83a9

Affected products (7)

• cpe:2.3:a:rubyonrails:rails:2.3.2:*:*:*:*:*:*:*
• cpe:2.3:a:rubyonrails:rails:2.3.3:*:*:*:*:*:*:*
• cpe:2.3:a:rubyonrails:rails:2.3.4:*:*:*:*:*:*:*
• cpe:2.3:a:rubyonrails:rails:2.3.9:*:*:*:*:*:*:*
• cpe:2.3:a:rubyonrails:rails:2.3.10:*:*:*:*:*:*:*
• cpe:2.3:a:rubyonrails:rails:2.3.11:*:*:*:*:*:*:*
• cpe:2.3:a:rubyonrails:rails:2.3.12:*:*:*:*:*:*:*

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