CVE-2025-46551
JRuby-OpenSSL has hostname verification disabled by default
Description
### Summary When verifying SSL certificates, jruby-openssl is not verifying that the hostname presented in the certificate matches the one we are trying to connect to, meaning a MITM could just present _any_ valid cert for a completely different domain they own, and JRuby wouldn't complain. ### Details n/a ### PoC An example domain bad.substitutealert.com was created to present the a certificate for the domain s8a.me. The following script run in IRB in CRuby 3.4.3 will fail with `certificate verify failed (hostname mismatch)`, but will work just fine in JRuby 10.0.0.0 and JRuby 9.4.2.0, both of which use jruby-openssl version 0.15.3 ```ruby require "net/http" require "openssl" uri = URI("https://bad.substitutealert.com/") https = Net::HTTP.new(uri.host, uri.port) https.use_ssl = true https.verify_mode = OpenSSL::SSL::VERIFY_PEER body = https.start { https.get(uri.request_uri).body } puts body ``` ### Impact Anybody using JRuby to make requests of external APIs, or scraping the web, that depends on https to connect securely
How to fix CVE-2025-46551
To remediate CVE-2025-46551, upgrade the affected package to a fixed version below.
- —upgrade to 10.0.0.1 or later
- —upgrade to 0.15.4 or later
- —upgrade to 0.15.4 or later
Is CVE-2025-46551 being exploited?
Low — EPSS is 0.1%, meaning exploitation activity has not been observed at scale.
Affected packages (3)
- >= 10.0.0.0, < 10.0.0.1
- >= 0.12.1, < 0.15.4
- >= 0.12.1, < 0.15.4
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 4.0 | — | 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 |