CVE-2015-5352: The x11_open_helper function in channels.c in ssh in OpenSSH before 6.9, when ForwardX11Trusted mode is not...

Security readout for executives and security teams

CVE-2015-5352 is an OpenSSH client-side X11 forwarding flaw. In OpenSSH before 6.9, untrusted X11 forwarding could accept X connections after the intended timeout, weakening a time-based access restriction. Business impact is mainly legacy client exposure where X11 forwarding is still used. Exposure is most likely on legacy Unix, Linux, or appliance environments running OpenSSH client versions before 6.9 and using X11 forwarding. Vendor advisories from Ubuntu, Gentoo, Red Hat, SUSE, Debian LTS, Oracle, NetApp, and Siemens suggest broad ecosystem relevance, but the bundle does not enumerate exact affected versions. Treat this as a legacy exposure cleanup item unless X11 forwarding is used in sensitive administrative workflows. It does not have supplied evidence of active exploitation, but outdated OpenSSH clients should be removed or patched through normal vulnerability management. Mitigation focus: Update OpenSSH or vendor ssh packages to fixed supported versions.; Use vendor advisories for backported fixes on maintained distributions.; Disable X11 forwarding where it is not operationally required..

Prepared

Jun 13, 2026, 22:22 UTC (UTC+00:00)

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