CVE-2015-1855: verify_certificate_identity in the OpenSSL extension in Ruby before 2.0.0 patchlevel 645, 2.1.x before 2.1....

Security readout for executives and security teams

This flaw affects Ruby’s TLS certificate hostname checking in older Ruby releases. A connection could accept a certificate for the wrong host under specific wildcard, IDNA, case, or non-ASCII name conditions, enabling server spoofing. The main business risk is loss of trust in encrypted connections from legacy Ruby applications. Exposure is most likely in legacy Ruby applications or automation still running the listed vulnerable Ruby versions and making outbound TLS connections where Ruby performs certificate hostname verification. Prioritize remediation where legacy Ruby handles sensitive outbound connections, authentication, package retrieval, configuration management, or API calls. This is not documented as actively exploited here, but it can undermine TLS trust boundaries. Mitigation focus: Upgrade Ruby to 2.0.0-p645, 2.1.6, 2.2.2, or later supported releases.; Apply relevant operating system Ruby security updates from distribution advisories.; Check Ruby and vendor advisories before relying on backported package version strings..

Prepared

Jun 6, 2026, 04:48 UTC (UTC+00:00)

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.