Description
ssh in OpenSSH before 10.1 allows control characters in usernames that originate from certain possibly untrusted sources, potentially leading to code execution when a ProxyCommand is used. The untrusted sources are the command line and %-sequence expansion of a configuration file. (A configuration file that provides a complete literal username is not categorized as an untrusted source.)
References10
- marc.info/?l=openssh-unix-dev&m=175974522032149&w=2
- www.openssh.com/releasenotes.html#10.1p1
- www.openwall.com/lists/oss-security/2025/10/06/1
- www.openwall.com/lists/oss-security/2025/10/07/1
- www.openwall.com/lists/oss-security/2025/10/12/1
- www.vicarius.io/vsociety/posts/cve-2025-61984-detection-script-…
- www.vicarius.io/vsociety/posts/cve-2025-61984-mitigation-script…
- cert-portal.siemens.com/productcert/html/ssa-019113.html
- cert-portal.siemens.com/productcert/html/ssa-457936.html
- dgl.cx/2025/10/bash-a-newline-ssh-proxycommand-cve-2025-61984
Metrics
- CVSS 3.1
-
3.6
LOW
Score source: CNA
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N - EPSS — exploit probability
- 0% percentile: 40 · as of 9 November 2026
- CWE
- CWE-159
Could this be exploited in your environment?
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