How severe is CVE-2015-3900?

No CVSS score has been assigned to CVE-2015-3900 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2015-3900?

CVE-2015-3900 affects the following packages: rubygems-update (RubyGems), rubygems-update (RubyGems), rubygems-update (RubyGems). Ecosystems affected: RubyGems.

How do I fix CVE-2015-3900?

Update rubygems-update to 2.0.16 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2015-3900 is resolved across your whole dependency graph.

How do I detect CVE-2015-3900 in my RubyGems dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for rubygems-update, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2015-3900 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against CVE-2015-3900?

O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2015-3900 can be triaged on real exposure rather than presence alone.

Is CVE-2015-3900 actively exploited in the wild?

No public exploit code has been indexed for CVE-2015-3900 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2015-3900?

CVE-2015-3900 has an EPSS (Exploit Prediction Scoring System) score of 8.9%, placing it in the 95th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2015-3900?

CVE-2015-3900 is classified as CWE-254 (CWE-254). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2015-3900 published, and has it been updated?

CVE-2015-3900 was published on June 24, 2015 and was last updated on April 16, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

💎 RubyGems

Not in CISA KEV

CVE-2015-3900 — rubygems-update

CVE-2015-3900 is a CWE-254 vulnerability in rubygems-update. A fix is available for rubygems-update — see the affected versions and patch details below.

RubyGems vulnerable to DNS hijack attack

Also known asGHSA-wp3j-rvfp-624h

Published

Jun 24, 2015

Updated

Apr 16, 2026

Affected

3 pkgs

Patched

3 / 3

Exploits

None indexed

Exploitation data as of Sep 20, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

8.9%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs95th percentile — riskier than 95% of all scored CVEsHighest risk

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Real-World Exposure

3 pkgs affected

💎rubygems-update💎rubygems-update💎rubygems-update

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects RubyGems packages — download data is not available via public APIs for these ecosystems.

Description

RubyGems 2.0.x before 2.0.16, 2.2.x before 2.2.4, and 2.4.x before 2.4.7 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, aka a "DNS hijack attack."

Affected Packages

3 total 3 fixed

Ecosystem	Package	Vulnerable range	Fix
💎RubyGems	`rubygems-update`	≥ 2.0.0&&< 2.0.16	2.0.16`bundle update rubygems-update --conservative`
💎RubyGems	`rubygems-update`	≥ 2.2.0&&< 2.2.4	2.2.4`bundle update rubygems-update --conservative`
💎RubyGems	`rubygems-update`	≥ 2.4.0&&< 2.4.7	2.4.7`bundle update rubygems-update --conservative`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for rubygems-update, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update rubygems-update to 2.0.16 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2015-3900 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2015-3900 can be triaged on real exposure rather than presence alone.

Tailored to CVE-2015-3900. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatImportant

This issue did not affect the versions of rubygems as shipped with Red Hat Enterprise Linux 6, Red Hat Enterprise MRG 2.5, Red Hat Satellite 6, Red Hat Openstack 5, Red Hat Openshift Enterprise 2 as they did not include support for getting API endpoint using SRV DNS records. This issue did not affect the versions of…

Product	Fixed in	Advisory
Red Hat Software Collections for Red Hat Enterprise Linux 6	`rh-ruby22-ruby-0:2.2.2-12.el6`	RHSA-2015:1657

Frequently Asked Questions

O3 Security · Impact-Aware SCA

Is CVE-2015-3900 in your dependencies?

O3 Security finds CVE-2015-3900 across RubyGems dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

Scan my dependencies How O3 SCA works