CVE-2026-106555

In sshd in OpenSSH through 10.6, in certain environments such as QNX 6 and SCO OpenServer 5, sshd-session can unexpectedly have root privileges. This is related to the GatewayPorts and StreamLocalForwarding configuration options, and lack of support for file-descriptor passing and unprivileged allocation of PTY devices.

In sshd in OpenSSH through 10.6, use of the macOS 27 (or later) SDK has the side effect of loss of sandboxing, which is potentially unexpected.

In sshd in OpenSSH before 10.6, the value "none" for a configuration option is sometimes interpreted as a filename but was intended to mean that a feature is disabled.

In sshd in OpenSSH before 10.6, the restrict keyword (in authorized_keys) was supposed to apply to tunnel forwarding but was not enforced. This is a different vulnerability than CVE-2026-73283.

In sshd and ssh in OpenSSH before version 10.6, there is no check for whether the maximum packet length is exceeded during decompression of highly compressed data.

In ssh-keygen in OpenSSH before 10.6, certificates could have incorrect expiration times due to Daylight Saving mishandling. There can be a slightly more severe effect on users in certain Antarctic locations.

In sshd and ssh in OpenSSH before 10.6, an LZ77 dictionary coder can be used even though this is contraindicated by the arXiv 2609.07709 "Crossing the Streams" findings.

In sshd in OpenSSH before 10.6, credentials can incorrectly persist after failure of a GSSAPIAuthentication authentication attempt.

In sftp in OpenSSH before version 10.6, a server can trigger directory traversal (causing files to be written to unintended locations) during a recursive copy operation.

The auth_password function in sshd in OpenSSH before version 7.3 does not limit password lengths for authentication, allowing remote attackers to cause a denial of service via long strings.