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CVE-2015-1855

MEDIUM · 5.9 CVSS v3.1 Published 2019-11-29
Fix available
A fix is available. Upgrade to 2.1.6 / 2.2.2 or later.
See remediation →
68/100
Remediation priority · Elevated
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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 summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

The verify_certificate_identity function in Ruby's OpenSSL extension fails to properly validate hostnames against SSL/TLS certificates. Specific flaws include improper handling of multiple wildcards in a single certificate name, incorrect validation of wildcards in Internationalized Domain Names (IDNA), case-sensitive hostname comparisons instead of case-insensitive, and mishandling of non-ASCII characters. These weaknesses allow remote attackers to spoof legitimate HTTPS servers using specially crafted certificates.

MitigationUpgrade Ruby to version 2.0.0p645, 2.1.6, 2.2.2 or later to include the fixed verify_certificate_identity implementation. For legacy systems that cannot upgrade, consider implementing hostname verification logic at the application layer using more robust libraries.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
RubyApplication
Affected:>= 2.1.0, < 2.1.6>= 2.2.0, < 2.2.2= 2.0.0
Debian LinuxOperating system
Affected:= 7.0= 8.0= 9.0
TrunkApplication
Affected:< 50292
Puppet AgentApplication
Affected:= 1.0.0
Puppet EnterpriseApplication
Affected:>= 3.0.0, < 3.8.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check installed Ruby version
    Run 'ruby --version' or 'ruby -e "puts RUBY_VERSION"' to get the Ruby version number
    Affected if The version is 2.0.0 (any patch level), 2.1.0 through 2.1.5, or 2.2.0 through 2.2.1 (these are the vulnerable versions)
  2. Check Puppet Agent version
    Run 'puppet --version' or check the installed puppet-agent package version
    Affected if The version is exactly 1.0.0 (this version ships with vulnerable Ruby)
  3. Check Puppet Enterprise version
    Run 'puppet --version' on a Puppet Enterprise node or check the PE version via the console or 'puppet-enterprise-installer --version'
    Affected if The version is 3.0.0 through 3.7.x (these ship with vulnerable Ruby)
  4. Verify SSL/TLS certificate verification is in use
    Review application code for use of Net::HTTP, OpenSSL::SSL, or any Ruby library that performs HTTPS connections with certificate verification enabled (verify_mode set to VERIFY_PEER)
    Affected if Your Ruby code makes HTTPS requests that verify server certificates AND you are running a vulnerable Ruby version listed above - the vulnerability only affects connections that perform hostname verification

You are affected if you run any of the vulnerable Ruby versions (2.0.0, 2.1.0-2.1.5, or 2.2.0-2.2.1) or vulnerable Puppet versions (Agent 1.0.0 or Enterprise 3.0.0-3.7.x) AND your application performs HTTPS connections that verify SSL/TLS certificates using Ruby's built-in OpenSSL extension.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Upgrade available Upgrade to 2.1.6 / 2.2.2 / 3.8.0 or later
Fixed in 2.1.62.2.23.8.0
Interim mitigation

Upgrade Ruby to version 2.0.0p645, 2.1.6, 2.2.2 or later to include the fixed verify_certificate_identity implementation. For legacy systems that cannot upgrade, consider implementing hostname verification logic at the application layer using more robust libraries.

Fix this in Ruby Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA3.0 h
21.0 hours of engineering $3,680
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2015-1855 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data