-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 Format: 1.8 Date: Fri, 15 May 2026 13:06:31 +0100 Source: openssh Architecture: source Version: 1:8.4p1-5+deb11u7 Distribution: bullseye-security Urgency: medium Maintainer: Debian OpenSSH Maintainers <debian-ssh@lists.debian.org> Changed-By: Colin Watson <cjwatson@debian.org> Closes: 1117529 1117530 1132572 1132573 1132574 1132575 1132576 Changes: openssh (1:8.4p1-5+deb11u7) bullseye-security; urgency=medium . * CVE-2025-61984: ssh(1): disallow control characters in usernames passed via the commandline (closes: #1117529). * CVE-2025-61985: ssh(1): disallow \0 characters in ssh:// URIs (closes: #1117530). * Backport minor security fixes from 10.3p1: - ssh(1): the -J and equivalent -oProxyJump="..." options now validate user and host names for ProxyJump/-J options passed via the command-line (no such validation is performed for this option in configuration files). This prevents shell injection in situations where these were directly exposed to adversarial input, which would have been a terrible idea to begin with. - CVE-2026-35386: ssh(1): validation of shell metacharacters in user names supplied on the command-line was performed too late to prevent some situations where they could be expanded from %-tokens in ssh_config. For certain configurations, such as those that use a "%u" token in a "Match exec" block, an attacker who can control the user name passed to ssh(1) could potentially execute arbitrary shell commands. Reported by Florian Kohnhäuser (closes: #1132573). We continue to recommend against directly exposing ssh(1) and other tools' command-lines to untrusted input. Mitigations such as this can not be absolute given the variety of shells and user configurations in use. - CVE-2026-35414: sshd(8): when matching an authorized_keys principals="" option against a list of principals in a certificate, an incorrect algorithm was used that could allow inappropriate matching in cases where a principal name in the certificate contains a comma character. Exploitation of the condition requires an authorized_keys principals="" option that lists more than one principal *and* a CA that will issue a certificate that encodes more than one of these principal names separated by a comma (typical CAs strongly constrain which principal names they will place in a certificate). This condition only applies to user- trusted CA keys in authorized_keys, the main certificate authentication path (TrustedUserCAKeys/AuthorizedPrincipalsFile) is not affected. Reported by Vladimir Tokarev (closes: #1132576). - CVE-2026-35385: scp(1): when downloading files as root in legacy (-O) mode and without the -p (preserve modes) flag set, scp did not clear setuid/setgid bits from downloaded files as one might typically expect. This bug dates back to the original Berkeley rcp program. Reported by Christos Papakonstantinou of Cantina and Spearbit (closes: #1132572). - CVE-2026-35387: sshd(8): fix incomplete application of PubkeyAcceptedAlgorithms and HostbasedAcceptedAlgorithms with regard to ECDSA keys. Previously if one of these directives contains any ECDSA algorithm name (say "ecdsa-sha2-nistp384"), then any other ECDSA algorithm would be accepted in its place regardless of whether it was listed or not. Reported by Christos Papakonstantinou of Cantina and Spearbit (closes: #1132574). - CVE-2026-35388: ssh(1): connection multiplexing confirmation (requested using "ControlMaster ask/autoask") was not being tested for proxy mode multiplexing sessions (i.e. "ssh -O proxy ..."). Reported by Michalis Vasileiadis (closes: #1132575). 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