CVE-2026-35388

OpenSSH before 10.3 omits connection multiplexing confirmation for proxy-mode multiplexing sessions.

OpenSSH before 10.3 omits connection multiplexing confirmation for proxy-mode multiplexing sessions.

An open source implementation of SSH protocol version 2

Security Fix(es):

Vulnerability in the OpenSSH GSSAPI delta included in various Linux distributions. This vulnerability affects the GSSAPI patches added by various Linux distributions and does not affect the OpenSSH upstream project itself. The usage of sshpkt_disconnect() on an error, which does not terminate the process, allows an attacker to send an unexpected GSSAPI message type during the GSSAPI key exchange to the server, which will call the underlying function and continue the execution of the program without setting the related connection variables. As the variables are not initialized to NULL the code later accesses those uninitialized variables, accessing random memory, which could lead to undefined behavior. The recommended workaround is to use ssh_packet_disconnect() instead, which does terminate the process. The impact of the vulnerability depends heavily on the compiler flag hardening configuration.(CVE-2026-3497)

In OpenSSH before 10.3, a file downloaded by scp may be installed setuid or setgid, an outcome contrary to some users' expectations, if the download is performed as root with -O (legacy scp protocol) and without -p (preserve mode).(CVE-2026-35385)

In OpenSSH before 10.3, command execution can occur via shell metacharacters in a username within a command line. This requires a scenario where the username on the command line is untrusted, and also requires a non-default configurations of % in ssh_config.(CVE-2026-35386)

OpenSSH before 10.3 can use unintended ECDSA algorithms. Listing of any ECDSA algorithm in PubkeyAcceptedAlgorithms or HostbasedAcceptedAlgorithms is misinterpreted to mean all ECDSA algorithms.(CVE-2026-35387)

OpenSSH before 10.3 omits connection multiplexing confirmation for proxy-mode multiplexing sessions.(CVE-2026-35388)

OpenSSH before 10.3 mishandles the authorized_keys principals option in uncommon scenarios involving a principals list in conjunction with a Certificate Authority that makes certain use of comma characters.(CVE-2026-35414)

OpenSSH is an SSH protocol implementation supported by a number of Linux, UNIX, and similar operating systems. It includes the core files necessary for both the OpenSSH client and server.

Security Fix(es):

• OpenSSH: OpenSSH: Privilege escalation via scp legacy protocol when not preserving file mode (CVE-2026-35385)

• OpenSSH: OpenSSH: Security bypass via mishandling of authorized_keys principals option (CVE-2026-35414)

• OpenSSH: OpenSSH: Information disclosure due to unintended cryptographic algorithm usage (CVE-2026-35387)

• OpenSSH: OpenSSH: Low integrity impact from unconfirmed proxy-mode multiplexing sessions (CVE-2026-35388)

• OpenSSH: OpenSSH: Arbitrary command execution via shell metacharacters in username (CVE-2026-35386)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

OpenSSH is an SSH protocol implementation supported by a number of Linux, UNIX, and similar operating systems. It includes the core files necessary for both the OpenSSH client and server.

Security Fix(es):

• OpenSSH: OpenSSH: Privilege escalation via scp legacy protocol when not preserving file mode (CVE-2026-35385)

• OpenSSH: OpenSSH: Security bypass via mishandling of authorized_keys principals option (CVE-2026-35414)

• OpenSSH: OpenSSH: Information disclosure due to unintended cryptographic algorithm usage (CVE-2026-35387)

• OpenSSH: OpenSSH: Low integrity impact from unconfirmed proxy-mode multiplexing sessions (CVE-2026-35388)

• OpenSSH: OpenSSH: Arbitrary command execution via shell metacharacters in username (CVE-2026-35386)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

OpenSSH is an SSH protocol implementation supported by a number of Linux, UNIX, and similar operating systems. It includes the core files necessary for both the OpenSSH client and server.

Security Fix(es):

• OpenSSH: OpenSSH: Privilege escalation via scp legacy protocol when not preserving file mode (CVE-2026-35385)

• OpenSSH: OpenSSH: Security bypass via mishandling of authorized_keys principals option (CVE-2026-35414)

• OpenSSH: OpenSSH: Information disclosure due to unintended cryptographic algorithm usage (CVE-2026-35387)

• OpenSSH: OpenSSH: Low integrity impact from unconfirmed proxy-mode multiplexing sessions (CVE-2026-35388)

• OpenSSH: OpenSSH: Arbitrary command execution via shell metacharacters in username (CVE-2026-35386)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

OpenSSH is an SSH protocol implementation supported by a number of Linux, UNIX, and similar operating systems. It includes the core files necessary for both the OpenSSH client and server.

Security Fix(es):

• OpenSSH: OpenSSH: Privilege escalation via scp legacy protocol when not preserving file mode (CVE-2026-35385)

• OpenSSH: OpenSSH: Security bypass via mishandling of authorized_keys principals option (CVE-2026-35414)

• OpenSSH: OpenSSH: Information disclosure due to unintended cryptographic algorithm usage (CVE-2026-35387)

• OpenSSH: OpenSSH: Low integrity impact from unconfirmed proxy-mode multiplexing sessions (CVE-2026-35388)

• OpenSSH: OpenSSH: Arbitrary command execution via shell metacharacters in username (CVE-2026-35386)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

OpenSSH is an SSH protocol implementation supported by a number of Linux, UNIX, and similar operating systems. It includes the core files necessary for both the OpenSSH client and server.

Security Fix(es):

• OpenSSH: OpenSSH: Privilege escalation via scp legacy protocol when not preserving file mode (CVE-2026-35385)

• OpenSSH: OpenSSH: Security bypass via mishandling of authorized_keys principals option (CVE-2026-35414)

• OpenSSH: OpenSSH: Information disclosure due to unintended cryptographic algorithm usage (CVE-2026-35387)

• OpenSSH: OpenSSH: Low integrity impact from unconfirmed proxy-mode multiplexing sessions (CVE-2026-35388)

• OpenSSH: OpenSSH: Arbitrary command execution via shell metacharacters in username (CVE-2026-35386)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

OpenSSH before 10.3 omits connection multiplexing confirmation for proxy-mode multiplexing sessions.

OpenSSH is an SSH protocol implementation supported by a number of Linux, UNIX, and similar operating systems. It includes the core files necessary for both the OpenSSH client and server.

Security Fix(es):

• OpenSSH: OpenSSH: Privilege escalation via scp legacy protocol when not preserving file mode (CVE-2026-35385)
• OpenSSH: OpenSSH: Security bypass via mishandling of authorized_keys principals option (CVE-2026-35414)
• OpenSSH: OpenSSH: Information disclosure due to unintended cryptographic algorithm usage (CVE-2026-35387)
• OpenSSH: OpenSSH: Low integrity impact from unconfirmed proxy-mode multiplexing sessions (CVE-2026-35388)
• OpenSSH: OpenSSH: Arbitrary command execution via shell metacharacters in username (CVE-2026-35386)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

OpenSSH is an SSH protocol implementation supported by a number of Linux, UNIX, and similar operating systems. It includes the core files necessary for both the OpenSSH client and server.

Security Fix(es):

• OpenSSH: OpenSSH: Privilege escalation via scp legacy protocol when not preserving file mode (CVE-2026-35385)
• OpenSSH: OpenSSH: Security bypass via mishandling of authorized_keys principals option (CVE-2026-35414)
• OpenSSH: OpenSSH: Information disclosure due to unintended cryptographic algorithm usage (CVE-2026-35387)
• OpenSSH: OpenSSH: Low integrity impact from unconfirmed proxy-mode multiplexing sessions (CVE-2026-35388)
• OpenSSH: OpenSSH: Arbitrary command execution via shell metacharacters in username (CVE-2026-35386)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

OpenSSH is an SSH protocol implementation supported by a number of Linux, UNIX, and similar operating systems. It includes the core files necessary for both the OpenSSH client and server.

Security Fix(es):

• OpenSSH: OpenSSH: Privilege escalation via scp legacy protocol when not preserving file mode (CVE-2026-35385)
• OpenSSH: OpenSSH: Security bypass via mishandling of authorized_keys principals option (CVE-2026-35414)
• OpenSSH: OpenSSH: Information disclosure due to unintended cryptographic algorithm usage (CVE-2026-35387)
• OpenSSH: OpenSSH: Low integrity impact from unconfirmed proxy-mode multiplexing sessions (CVE-2026-35388)
• OpenSSH: OpenSSH: Arbitrary command execution via shell metacharacters in username (CVE-2026-35386)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

OpenSSH is an SSH protocol implementation supported by a number of Linux, UNIX, and similar operating systems. It includes the core files necessary for both the OpenSSH client and server.

Security Fix(es):

• OpenSSH: OpenSSH: Privilege escalation via scp legacy protocol when not preserving file mode (CVE-2026-35385)
• OpenSSH: OpenSSH: Security bypass via mishandling of authorized_keys principals option (CVE-2026-35414)
• OpenSSH: OpenSSH: Information disclosure due to unintended cryptographic algorithm usage (CVE-2026-35387)
• OpenSSH: OpenSSH: Low integrity impact from unconfirmed proxy-mode multiplexing sessions (CVE-2026-35388)
• OpenSSH: OpenSSH: Arbitrary command execution via shell metacharacters in username (CVE-2026-35386)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

OpenSSH is an SSH protocol implementation supported by a number of Linux, UNIX, and similar operating systems. It includes the core files necessary for both the OpenSSH client and server.

Security Fix(es):

• OpenSSH: OpenSSH: Privilege escalation via scp legacy protocol when not preserving file mode (CVE-2026-35385)
• OpenSSH: OpenSSH: Security bypass via mishandling of authorized_keys principals option (CVE-2026-35414)
• OpenSSH: OpenSSH: Information disclosure due to unintended cryptographic algorithm usage (CVE-2026-35387)
• OpenSSH: OpenSSH: Low integrity impact from unconfirmed proxy-mode multiplexing sessions (CVE-2026-35388)
• OpenSSH: OpenSSH: Arbitrary command execution via shell metacharacters in username (CVE-2026-35386)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

OpenSSH before 10.3 omits connection multiplexing confirmation for proxy-mode multiplexing sessions.

• CVE-2026-35387: correctly match ECDSA signature algorithms against HostKeyAlgorithms, PubkeyAcceptedAlgorithms and HostbasedAcceptedAlgorithms
• CVE-2026-35388: add missing askpass check when using ControlMaster=ask/autoask and "ssh -O proxy ..."
• CVE-2026-35414: fix authorized_keys principals option matching to compare comma-separated entries individually instead of using match_list

• CVE-2026-35387: correctly match ECDSA signature algorithms against HostKeyAlgorithms, PubkeyAcceptedAlgorithms and HostbasedAcceptedAlgorithms
• CVE-2026-35388: add missing askpass check when using ControlMaster=ask/autoask and "ssh -O proxy ..."
• CVE-2026-35414: fix authorized_keys principals option matching to compare comma-separated entries individually instead of using match_list

In OpenSSH before 10.3, a file downloaded by scp may be installed setuid or setgid, an outcome contrary to some users' expectations, if the download is performed as root with -O (legacy scp protocol) and without -p (preserve mode). (CVE-2026-35385) In OpenSSH before 10.3, command execution can occur via shell metacharacters in a username within a command line. This requires a scenario where the username on the command line is untrusted, and also requires a non-default configurations of % in ssh_config. (CVE-2026-35386) OpenSSH before 10.3 can use unintended ECDSA algorithms. Listing of any ECDSA algorithm in PubkeyAcceptedAlgorithms or HostbasedAcceptedAlgorithms is misinterpreted to mean all ECDSA algorithms. (CVE-2026-35387) OpenSSH before 10.3 omits connection multiplexing confirmation for proxy-mode multiplexing sessions. (CVE-2026-35388) OpenSSH before 10.3 mishandles the authorized_keys principals option in uncommon scenarios involving a principals list in conjunction with a Certificate Authority that makes certain use of comma characters. (CVE-2026-35414)

These are all security issues fixed in the openssh-10.3p1-6.1 package on the GA media of openSUSE Tumbleweed.

This update for openssh fixes the following issues

Security fixes:

• CVE-2026-3497: information disclosure or denial of service due to uninitialized variables (bsc#1259642).
• CVE-2026-35388: omitted connection multiplexing confirmation for proxy-mode multiplexing sessions (bsc#1261441).
• openssh potential security issue when validating mac or ciphers (bsc#1264568).

Other fixes:

• Improve %prep LDAP regex to preserve subdirectories (e.g., openbsd-compat/) and handle optional [ab]/ prefixes.

This update for openssh fixes the following issues:

• CVE-2026-35388: Added missing askpass check for proxy-mode multiplexing sessions (bsc#1261441)
• CVE-2026-3497: Fixed a possible information disclosure or denial of service due to uninitialized variables in gssapi patches (bsc#1259642)
• Add patch to fix a potential issue when validating mac or ciphers

This update for openssh fixes the following issues

Security fixes:

• CVE-2026-3497: information disclosure or denial of service due to uninitialized variables (bsc#1259642).
• CVE-2026-35388: omitted connection multiplexing confirmation for proxy-mode multiplexing sessions (bsc#1261441).
• openssh potential security issue when validating mac or ciphers (bsc#1264568).

Other fixes:

• Improve %prep LDAP regex to preserve subdirectories (e.g., openbsd-compat/) and handle optional [ab]/ prefixes.

This update for openssh fixes the following issues

Security fixes:

• CVE-2026-3497: information disclosure or denial of service due to uninitialized variables (bsc#1259642).
• CVE-2026-35388: omitted connection multiplexing confirmation for proxy-mode multiplexing sessions (bsc#1261441).
• openssh potential security issue when validating mac or ciphers (bsc#1264568).

Other fixes:

• Improve %prep LDAP regex to preserve subdirectories (e.g., openbsd-compat/) and handle optional [ab]/ prefixes.

This update for openssh fixes the following issues:

• CVE-2025-32728: fix logic error in DisableForwarding option (bsc#1241012).
• CVE-2026-3497: information disclosure or denial of service due to uninitialized variables (bsc#1259642).
• CVE-2026-35385: a file downloaded by scp may be installed setuid or setgid (bsc#1261427).

Other issues fixed::

• ignores write permissions for Group and World Directory Permissions (bsc#1241667).
• wall tool not longer printing any message to terminals (bsc#1239671)
• potential issue in validating mac (bsc#1264568):

• Improve %prep LDAP regex to preserve subdirectories (e.g., ope- nbsd-compat/) and handle optional [ab]/ prefixes.

This update for openssh fixes the following issues

• CVE-2026-3497: information disclosure or denial of service due to uninitialized variables (bsc#1259642).
• CVE-2026-35385: a file downloaded by scp may be installed setuid or setgid (bsc#1261427).
• CVE-2026-35388: omitted connection multiplexing confirmation for proxy-mode multiplexing sessions (bsc#1261441).
• CVE-2026-35414: mishandling of authorized_keys principals option (bsc#1261430).
• potential security issue when validating mac (bsc#1264568).

This update for openssh fixes the following issues

• CVE-2026-3497: information disclosure or denial of service due to uninitialized variables (bsc#1259642).
• CVE-2026-35385: a file downloaded by scp may be installed setuid or setgid (bsc#1261427).
• CVE-2026-35388: omitted connection multiplexing confirmation for proxy-mode multiplexing sessions (bsc#1261441).
• CVE-2026-35414: mishandling of authorized_keys principals option (bsc#1261430).
• potential security issue when validating mac (bsc#1264568).

This update for openssh8.4 fixes the following issues

• CVE-2026-3497: Information disclosure or denial of service due to uninitialized variables (bsc#1259642).
• CVE-2026-35385: a file downloaded by scp may be installed setuid or setgid (bsc#1261427).
• CVE-2026-35388: omitted connection multiplexing confirmation for proxy-mode multiplexing sessions (bsc#1261441).
• CVE-2026-35414: mishandling of authorized_keys principals option (bsc#1261430).
• potential security issue in validating mac (bsc#1264568).