HOME VULNERABILITIESCVE-2015-1855

MEDIUM

CVE-2015-1855

CWE-20Published: November 29, 2019· Updated: Jun 17, 2026

5.9

CVSS v3.1

Official Description

verify_certificate_identity in the OpenSSL extension in Ruby before 2.0.0 patchlevel 645, 2.1.x before 2.1.6, and 2.2.x before 2.2.2 does not properly validate hostnames, which allows remote attackers to spoof servers via vectors related to (1) multiple wildcards, (1) wildcards in IDNA names, (3) case sensitivity, and (4) non-ASCII characters.

Technical Analysis

CVE-2015-1855 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in full integrity compromise (data manipulation), with a CVSS base score of 5.9.

CVSS v3.1 Vector Breakdown

Exploitability

Attack VectorNetwork

Attack ComplexityHigh

Privileges Req.None

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityHigh

AvailabilityNone

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N

Affected Vendors & Products

Debian1 product(s)

debian linux

puppet2 product(s)

puppet agentpuppet enterprise

ruby-lang2 product(s)

rubytrunk

Source: NVD CPE · 8 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time

Offensive Security exploit database

GitHub PoC Search

Community PoC repositories

Rapid7 / Metasploit

Metasploit module search

Security advisories & exploits

Official NIST entry

CVE Program entry

External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

ADVISORYhttp://www.debian.org/security/2015/dsa-3245

ADVISORYhttp://www.debian.org/security/2015/dsa-3246

ADVISORYhttp://www.debian.org/security/2015/dsa-3247

ADVISORYhttps://bugs.ruby-lang.org/issues/9644

ADVISORYhttps://puppetlabs.com/security/cve/cve-2015-1855

ADVISORYhttps://www.ruby-lang.org/en/news/2015/04/13/ruby-openssl-hostname-matching-vulnerability/

ADVISORYhttp://www.debian.org/security/2015/dsa-3245

ADVISORYhttp://www.debian.org/security/2015/dsa-3246

ADVISORYhttp://www.debian.org/security/2015/dsa-3247

ADVISORYhttps://bugs.ruby-lang.org/issues/9644

ADVISORYhttps://puppetlabs.com/security/cve/cve-2015-1855

ADVISORYhttps://www.ruby-lang.org/en/news/2015/04/13/ruby-openssl-hostname-matching-vulnerability/

All References (12)

→

http://www.debian.org/security/2015/dsa-3245Third Party Advisory

→

http://www.debian.org/security/2015/dsa-3246Third Party Advisory

→

http://www.debian.org/security/2015/dsa-3247Third Party Advisory

→

https://bugs.ruby-lang.org/issues/9644Third Party Advisory

→

https://puppetlabs.com/security/cve/cve-2015-1855Third Party Advisory

→

https://www.ruby-lang.org/en/news/2015/04/13/ruby-openssl-hostname-matching-vulnerability/Vendor Advisory

→

http://www.debian.org/security/2015/dsa-3245Third Party Advisory

→

http://www.debian.org/security/2015/dsa-3246Third Party Advisory

→

http://www.debian.org/security/2015/dsa-3247Third Party Advisory

→

https://bugs.ruby-lang.org/issues/9644Third Party Advisory

→

https://puppetlabs.com/security/cve/cve-2015-1855Third Party Advisory

→

https://www.ruby-lang.org/en/news/2015/04/13/ruby-openssl-hostname-matching-vulnerability/Vendor Advisory

Quick Facts

CVE IDCVE-2015-1855

CVSS Score5.9 / 10

SeverityMEDIUM

WeaknessCWE-20

CISA KEVNo

Affected3 vendor(s)

PublishedNov 29, 2019

Related CVEs (CWE-20)

Recommended Actions

→Apply vendor patches immediately
→Monitor CVE-2015-1855 in threat intel feeds
→Review IDS/IPS signatures for exploitation attempts

Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.

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