Ubuntu
openssh package

  1. Bug #1863930
  2. Comment #0

Comment 0 for bug 1863930

Revision history for this message
Kyle Birkeland (kbirkeland) wrote :

SSHD closes the connection and logs the error message below when a client presents a protoversion of "1.99":

    Protocol major versions differ for X.X.X.X port X: SSH-2.0-OpenSSH_7.6p1 Ubuntu-4ubuntu0.3 vs. SSH-1.99-XXX

RFC 4253 only states that clients should treat a server's protoversion of "1.99" as equivalent to "2.0"; however, some backward-compatible clients send a protoversion of "1.99" and expect the server to treat it as "2.0".

This regression was introduced in openssh-portable 7.6p1 from commit 97f4d3083; fixes were implemented in commits 9e9c4a7e5 and c9c1bba06. I've attached a patch with both of those fixes.