CVE-2009-3287: lib/thin/connection.rb in Thin web server before 1.2.4 relies on the X-Forwarded-For header to determine th...

Security readout for executives and security teams

Thin web server versions before 1.2.4 could trust a client-supplied X-Forwarded-For header as the client IP. A remote user could spoof that value, making logs, abuse tracking, or IP-based decisions unreliable for affected deployments. Exposure is likely limited to applications running Thin web server before 1.2.4, especially where logs, rate limits, allowlists, bans, or audit trails depend on the client IP reported by Thin. Treat as a targeted hygiene issue, not an emergency, unless affected Thin systems enforce security decisions by client IP. Prioritize upgrades where audit integrity, abuse response, or IP-based access controls matter. Mitigation focus: Upgrade Thin to version 1.2.4 or later if still deployed.; Check vendor changelog and commit guidance for the exact fixed behavior.; Avoid trusting client-supplied forwarding headers without a trusted proxy boundary..

Prepared

Jun 28, 2026, 18:15 UTC (UTC+00:00)

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