CVE-2026-3497
HighCVSS 7.5Exploitation Probability (EPSS)
High risk80th percentile - higher than 80% of all known CVEs
Summary
Vulnerability in OpenSSH GSSAPI patches added by various Linux distributions. The use of sshpkt_disconnect() instead of ssh_packet_disconnect() does not terminate the process, allowing an attacker to send an unexpected GSSAPI message type during key exchange, leading to access of uninitialized variables and potential undefined behavior.
Risk Assessment
An attacker could exploit this to achieve remote code execution or cause a denial of service on the SSH service, compromising confidentiality and availability. The risk depends on compiler flag hardening.
Recommendation
Apply the vendor patch that replaces sshpkt_disconnect() with ssh_packet_disconnect(). As a temporary workaround, consider disabling the GSSAPI extension in SSH configuration.
Other vulnerabilities in OpenSSH
See all- 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.
- CVE-2025-26465Medium
A vulnerability was found in OpenSSH when the VerifyHostKeyDNS option is enabled. A machine-in-the-middle attack can be performed by a malicious machine impersonating a legit server. This issue occurs due to how OpenSSH mishandles error codes in specific conditions when verifying the host key.
- CVE-2023-28531Critical
The vulnerability in ssh-add in OpenSSH before 9.3 adds smartcard keys to ssh-agent without the intended per-hop destination constraints. The earliest affected version is 8.9.
Original NVD description (English source)
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.