Improper Certificate Validation in EM-HTTP-RequestGHSA-q27f-v3r6-9v77
HIGHFix: igrigorik/em-http-request@e5fa144GHSA-q27f-v3r6-9v77 is a high-severity (CVSS 7.4) CWE-295 vulnerability in em-http-request. 2 public exploit references exist, so weaponization risk is real. A fix is available for em-http-request — see the affected versions and patch details below.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
GHSA-q27f-v3r6-9v77 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 385,738 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
em-http-requestReal-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
EM-HTTP-Request 1.1.5 uses the library eventmachine in an insecure way that allows an attacker to perform a man-in-the-middle attack against users of the library. The hostname in a TLS server certificate is not verified.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | em-http-request | all versions | 1.1.6bundle update em-http-request --conservative |
Affected Products
em-http-requestem-http-request_projectfedorafedoraprojectResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for em-http-request, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update em-http-request to 1.1.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-q27f-v3r6-9v77 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.
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 Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update as soon as possible.Source: Red Hat security advisory for GHSA-q27f-v3r6-9v77 (CC BY 4.0)
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat OpenStack Platform 13.0 Operational Tools for RHEL 7 | rubygem-em-http-request-0:1.1.5-4.el7ost | RHSA-2021:0937 |
Frequently Asked Questions
Is GHSA-q27f-v3r6-9v77 in your dependencies?
Find it across RubyGems, including transitive dependencies.