How severe is CVE-2015-1855?

CVE-2015-1855 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.

Is CVE-2015-1855 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (85th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2015-1855?

CVE-2015-1855 primarily affects Ruby-lang Ruby. In total, 18 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2015-1855?

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

When was CVE-2015-1855 published?

CVE-2015-1855 was published on 2019-11-29 and last updated on 2026-06-17.

CVE-2015-1855

CVE-2015-1855 is a medium-severity vulnerability in Ruby-lang Ruby with a CVSS 3.x base score of 5.9. 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-20.

Key facts

Severity: Medium (CVSS 3.x base score 5.9)
CVSS v2: 4.3
EPSS exploit prediction: 3% (85th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-20
Affected product: Ruby-lang Ruby
Published: 2019-11-29
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2015-1855?: 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.
How severe is CVE-2015-1855?: CVE-2015-1855 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.
Is CVE-2015-1855 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (85th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2015-1855?: CVE-2015-1855 primarily affects Ruby-lang Ruby. In total, 18 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2015-1855?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2015-1855 published?: CVE-2015-1855 was published on 2019-11-29 and last updated on 2026-06-17.

References

Affected products (18)

cpe:2.3:a:ruby-lang:ruby:*:*:*:*:*:*:*:*
cpe:2.3:a:ruby-lang:ruby:2.0.0:-:*:*:*:*:*:*
cpe:2.3:a:ruby-lang:ruby:2.0.0:p0:*:*:*:*:*:*
cpe:2.3:a:ruby-lang:ruby:2.0.0:p195:*:*:*:*:*:*
cpe:2.3:a:ruby-lang:ruby:2.0.0:p247:*:*:*:*:*:*
cpe:2.3:a:ruby-lang:ruby:2.0.0:p353:*:*:*:*:*:*
cpe:2.3:a:ruby-lang:ruby:2.0.0:p451:*:*:*:*:*:*
cpe:2.3:a:ruby-lang:ruby:2.0.0:p481:*:*:*:*:*:*
cpe:2.3:a:ruby-lang:ruby:2.0.0:p576:*:*:*:*:*:*
cpe:2.3:a:ruby-lang:ruby:2.0.0:p594:*:*:*:*:*:*
cpe:2.3:a:ruby-lang:ruby:2.0.0:p598:*:*:*:*:*:*
cpe:2.3:a:ruby-lang:ruby:2.0.0:p643:*:*:*:*:*:*
cpe:2.3:a:ruby-lang:trunk:*:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:7.0:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
cpe:2.3:a:puppet:puppet_agent:1.0.0:*:*:*:*:*:*:*
cpe:2.3:a:puppet:puppet_enterprise:*:*:*:*:*:*:*:*

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