CVE-2025-46551: JRuby-OpenSSL has hostname verification disabled by default
Description
JRuby-OpenSSL is an add-on gem for JRuby that emulates the Ruby OpenSSL native library. Starting in JRuby-OpenSSL version 0.12.1 and prior to version 0.15.4 (corresponding to JRuby versions starting in 9.3.4.0 prior to 9.4.12.1 and 10.0.0.0 prior to 10.0.0.1), when verifying SSL certificates, JRuby-OpenSSL does not verify that the hostname presented in the certificate matches the one the user tries to connect to. This means a man-in-the-middle could just present any valid cert for a completely different domain they own, and JRuby would accept the cert. Anybody using JRuby to make requests of external APIs, or scraping the web, that depends on https to connect securely. JRuby-OpenSSL version 0.15.4 contains a fix for the issue. This fix is included in JRuby versions 10.0.0.1 and 9.4.12.1.
Classification
CVE ID: CVE-2025-46551
CVSS Base Severity: MEDIUM
CVSS Base Score: 5.7
CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P
Problem Types
CWE-295: Improper Certificate ValidationAffected Products
Vendor: jruby
Product: jruby-openssl
Exploit Prediction Scoring System (EPSS)
EPSS Score: 0.03% (probability of being exploited)
EPSS Percentile: 5.26% (scored less or equal to compared to others)
EPSS Date: 2025-06-05 (when was this score calculated)
References
https://nvd.nist.gov/vuln/detail/CVE-2025-46551https://github.com/jruby/jruby-openssl/security/advisories/GHSA-72qj-48g4-5xgx
https://github.com/jruby/jruby-openssl/commit/31a56d690ce9b8af47af09aaaf809081949ed285