CVE-2015-4020

Severity: medium (CVSS 4.3 v2.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 3.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2015-08-25 · updated 2026-06-17
Weakness: CWE-20

Description

RubyGems 2.0.x before 2.0.17, 2.2.x before 2.2.5, and 2.4.x before 2.4.8 does not validate the hostname when fetching gems or making API requests, which allows remote attackers to redirect requests to arbitrary domains via a crafted DNS SRV record with a domain that is suffixed with the original domain name, aka a "DNS hijack attack." NOTE: this vulnerability exists because to an incomplete fix for CVE-2015-3900.

Affected products

Oracle Corporation Solaris Operating System: 11.3
rubygems: 2.0.0, 2.0.0-preview2, 2.0.0-preview2.1, 2.0.0-preview2.2, 2.0.0-rc1, 2.0.0-rc2 (+29)

References

http://blog.rubygems.org/2015/06/08/2.2.5-released.html
http://blog.rubygems.org/2015/06/08/2.4.8-released.html
http://www.oracle.com/technetwork/topics/security/bulletinoct2015-2511968.html
http://www.securityfocus.com/bid/75431
https://github.com/rubygems/rubygems/commit/5c7bfb5
https://puppet.com/security/cve/CVE-2015-3900
https://www.trustwave.com/Resources/Security-Advisories/Advisories/TWSL2015-009/?fid=6478
https://www.trustwave.com/Resources/SpiderLabs-Blog/Attacking-Ruby-Gem-Security-with-CVE-2015-3900/
http://blog.rubygems.org/2015/06/08/2.2.5-released.html
http://blog.rubygems.org/2015/06/08/2.4.8-released.html
http://www.oracle.com/technetwork/topics/security/bulletinoct2015-2511968.html
http://www.securityfocus.com/bid/75431

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