CVE-2026-35388

A flaw was found in OpenSSH. This vulnerability allows for a low integrity impact due to the omission of connection multiplexing confirmation for proxy-mode multiplexing sessions. A local user, under specific and complex conditions requiring user interaction, could potentially establish a multiplexed session without explicit confirmation, leading to unintended data handling.

Red Hat Product Security rates this vulnerability as having a Low impact because exploitation requires a non-default client configuration, local access to the user's multiplexing socket, and user interaction, with the blast radius limited to unauthorized channel multiplexing without interactive confirmation. In default Red Hat Enterprise Linux environments, OpenSSH connection multiplexing is disabled (ControlMaster no). The flaw only manifests when users explicitly configure ControlMaster with ask or autoask modes. Because standard system deployments do not enable connection sharing or interactive multiplex prompts, typical system operations remain unaffected.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.