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By Zayden R., July 7, 2026
OpenSSH 10.4, now available, introduces experimental support for a composite post-quantum signature scheme. This release also enforces sandbox support on Linux systems, enhancing security measures.
OpenSSH 10.4 has made its debut, bringing with it a raft of updates that are set to interest both security-focused developers and system administrators. Among the highlights of this release is the introduction of experimental support for a composite post-quantum signature scheme. This new feature combines ML-DSA 44 and Ed25519, aligning with the specifications outlined in a recent IETF draft. For those concerned about the looming threat of quantum computing on cryptographic security, this development is a promising step forward.
In addition to this forward-thinking security feature, OpenSSH 10.4 also introduces a more stringent approach to sandboxing. If the software is compiled with sandbox support, it will now refuse to run on Linux systems that have not enabled SECCOMP or NO_NEW_PRIVS. Previously, the sshd daemon would log an error but continue operating, a behavior that has now been tightened to enhance security.
This update also brings a host of security and bug fixes, ensuring that OpenSSH remains a robust tool in the sysadmin's toolkit. The release notes detail these changes more comprehensively, but the focus on security improvements is clear. OpenSSH continues to be a critical component for secure communications, and version 10.4 underscores its commitment to staying ahead of emerging threats.
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