CVE-2026-35388
LowCVSS 2.5Exploitation Probability (EPSS)
Low risk3th percentile - higher than 3% of all known CVEs
Summary
OpenSSH before version 10.3 omits connection multiplexing confirmation for proxy-mode multiplexing sessions, potentially allowing unauthorized access.
Risk Assessment
An attacker could exploit the missing confirmation to hijack a multiplexed session, leading to unauthorized system access.
Recommendation
Update OpenSSH to version 10.3 or later which enforces confirmation for proxy multiplexing.
Other vulnerabilities in OpenSSH
See all- CVE-2026-97811High
Double free in OpenSSH for Windows allows an authorized attacker to elevate privileges locally.
- CVE-2026-83923High
Relative path traversal in OpenSSH for Windows allows an unauthorized attacker to execute code over a network.
- CVE-2016-6515High
The auth_password function in sshd in OpenSSH before version 7.3 does not limit password lengths for authentication, allowing remote attackers to cause a denial of service via long strings.
- CVE-2015-8325High
The do_setup_env function in sshd in OpenSSH through 7.2p2, when the UseLogin feature is enabled and PAM is configured to read .pam_environment files in user home directories, allows local users to gain privileges by triggering a crafted environment for the /bin/login program.
- CVE-2015-5600High
The kbdint_next_device function in auth2-chall.c in sshd in OpenSSH through 6.9 does not properly restrict the processing of keyboard-interactive devices within a single connection. This allows remote attackers to conduct brute-force attacks or cause denial of service via a long and duplicative list in the ssh -oKbdInteractiveDevices option.
- CVE-2014-1692High
The hash_buffer function in schnorr.c in OpenSSH through 6.4, when Makefile.inc is modified to enable the J-PAKE protocol, does not initialize certain data structures. This may allow remote attackers to cause a denial of service (memory corruption) or have unspecified other impact via vectors that trigger an error condition.
- CVE-2025-32728Medium
In sshd in OpenSSH before version 10.0, the DisableForwarding directive does not adhere to documentation, failing to disable X11 and agent forwarding.
- CVE-2026-39832Critical
When adding a key to a remote agent, constraint extensions such as [email protected] were not serialized in the request. Destination restrictions were silently stripped when forwarding keys, allowing unrestricted use of the key on the remote host.
- CVE-2026-39831Critical
Vulnerability in the Verify() method for FIDO/U2F security keys ([email protected], [email protected]) – the User Presence flag was not checked. Signatures generated without physical touch were accepted, allowing unauthorized use of the key.
- CVE-2025-26466Medium
A flaw in the OpenSSH package causes each received ping packet to allocate a pong packet in memory, stored in a queue until key exchange completes. A malicious client can send such packets continuously, leading to uncontrolled memory consumption on the server.
Original NVD description (English source)
OpenSSH before 10.3 omits connection multiplexing confirmation for proxy-mode multiplexing sessions.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS

