Bug 2553034 (CVE-2026-110925) - CVE-2026-110925 openssh: openssh: '$' and '\' in a command-line username expand through %u
Summary: CVE-2026-110925 openssh: openssh: '$' and '\' in a command-line username expa...
Keywords:
Status: NEW
Alias: CVE-2026-110925
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-10-15 04:16 UTC by OSIDB Bzimport
Modified: 2026-10-15 04:45 UTC (History)
18 users (show)

Fixed In Version:
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Description OSIDB Bzimport 2026-10-15 04:16:27 UTC 
A flaw was found in OpenSSH ssh. ssh_valid_ruser did not reject '$' or a backslash that is not at the end of a username entered on the command line. Those characters still expand through %u in ProxyCommand or Match exec. Usernames written in the configuration file are not subject to this check. CVE-2026-35386 is already backported and rejects a different set of shell metacharacters, plus a trailing backslash. Hostnames in that fix already reject '$' and '\'. Usernames do not. This is a new CVE on top of CVE-2026-35386.
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