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.

Published: 2019-11-29 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2015-1855 is rated Moderate Risk (53.9/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 2.72%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2015-1855

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2025-12-28 2.38% 2.72% +0.34%
2 2025-12-27 2.72% 2.38% -0.34%
3 2025-10-28 — 2.72% —

Full EPSS history (22 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2015-1855

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.9 3.1 MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 2.2 3.6 [email protected]
4.3 2.0 MEDIUM
AV:N/AC:M/Au:N/C:N/I:P/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:N)
No availability impact.
 8.6 2.9 [email protected]

Weakness enumeration for CVE-2015-1855

OS Trackers for CVE-2015-1855

vendor priority summary link
alpine medium CVE-2015-1855: 1 source package rows (trunk); 11 state rows across 3 repos (3.22-community, 3.23-community, edge-community); fixed 0, open 11. https://security.alpinelinux.org/vuln/CVE-2015-1855
redhat medium — https://access.redhat.com/security/cve/CVE-2015-1855
suse medium CVE-2015-1855 severity moderate: SUSE including 65 source package names (4.0.0:libruby2_1-2_1-2.1.9-15.1, 4.0.0:ruby2.1-2.1.9-15.1, …), 499 product×package rows across 85 product lines (Container caasp/v4/velum, HPE Helion OpenStack 8, … (85 product lines)): Known Not Affected 349, Fixed 150. https://www.suse.com/security/cve/CVE-2015-1855/
ubuntu low CVE-2015-1855 low priority: Ubuntu including 6 source packages (ruby1.8, ruby1.9.1, ruby2.0, ruby2.1, ruby2.2, ruby2.3), 60 status rows across 10 suites (lucid, precise, trusty, upstream, utopic, vivid, wily, xenial, yakkety, zesty): DNE 38, ignored 9, not-affected 5, needed 4, released 4. https://ubuntu.com/security/CVE-2015-1855

Affected software / configurations for CVE-2015-1855

Vendor Product Version Raw CPE
ruby-lang ruby >= 2.1.0, < 2.1.6 cpe:2.3:a:ruby-lang:ruby:*:*:*:*:*:*:*:*
ruby-lang ruby >= 2.2.0, < 2.2.2 cpe:2.3:a:ruby-lang:ruby:*:*:*:*:*:*:*:*
ruby-lang ruby 2.0.0 cpe:2.3:a:ruby-lang:ruby:2.0.0:-:*:*:*:*:*:*
ruby-lang ruby 2.0.0 cpe:2.3:a:ruby-lang:ruby:2.0.0:p0:*:*:*:*:*:*
ruby-lang ruby 2.0.0 cpe:2.3:a:ruby-lang:ruby:2.0.0:p195:*:*:*:*:*:*
ruby-lang ruby 2.0.0 cpe:2.3:a:ruby-lang:ruby:2.0.0:p247:*:*:*:*:*:*
ruby-lang ruby 2.0.0 cpe:2.3:a:ruby-lang:ruby:2.0.0:p353:*:*:*:*:*:*
ruby-lang ruby 2.0.0 cpe:2.3:a:ruby-lang:ruby:2.0.0:p451:*:*:*:*:*:*
ruby-lang ruby 2.0.0 cpe:2.3:a:ruby-lang:ruby:2.0.0:p481:*:*:*:*:*:*
ruby-lang ruby 2.0.0 cpe:2.3:a:ruby-lang:ruby:2.0.0:p576:*:*:*:*:*:*
ruby-lang ruby 2.0.0 cpe:2.3:a:ruby-lang:ruby:2.0.0:p594:*:*:*:*:*:*
ruby-lang ruby 2.0.0 cpe:2.3:a:ruby-lang:ruby:2.0.0:p598:*:*:*:*:*:*
ruby-lang ruby 2.0.0 cpe:2.3:a:ruby-lang:ruby:2.0.0:p643:*:*:*:*:*:*
ruby-lang trunk < 50292 cpe:2.3:a:ruby-lang:trunk:*:*:*:*:*:*:*:*
debian debian_linux 7.0 cpe:2.3:o:debian:debian_linux:7.0:*:*:*:*:*:*:*
debian debian_linux 8.0 cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*
debian debian_linux 9.0 cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
puppet puppet_agent 1.0.0 cpe:2.3:a:puppet:puppet_agent:1.0.0:*:*:*:*:*:*:*
puppet puppet_enterprise >= 3.0.0, < 3.8.0 cpe:2.3:a:puppet:puppet_enterprise:*:*:*:*:*:*:*:*

References for CVE-2015-1855

cvelogic Threat Intelligence