CVE-2026-55654
LowCVSS 3.7Exploitation Probability (EPSS)
Low risk49th percentile - higher than 49% of all known CVEs
Summary
A heap out-of-bounds read flaw was found in OpenSSH during cleanup of GSSAPI indicators when a trailing NULL is missing in the auth-indicators array. A remote attacker, under specific configurations with GSSAPI authentication and a Kerberos environment, could exploit this to crash the SSH authentication path, causing a denial of service (DoS).
Risk Assessment
The risk involves potential disruption of SSH service availability, which could block remote access to servers and impact critical organizational systems.
Recommendation
It is recommended to immediately update OpenSSH to the latest patched version and, if possible, temporarily disable GSSAPI authentication in the SSH configuration until the patch is applied.
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)
A flaw was found in OpenSSH. This vulnerability, a heap out-of-bounds read, occurs during the cleanup of GSSAPI (Generic Security Service Application Programming Interface) indicators when a trailing NULL termination is missing in the auth-indicators array. A remote attacker, under specific configurations involving GSSAPI authentication and a Kerberos environment, could exploit this to cause the SSH authentication path to crash or abort. This leads to a denial of service (DoS), impacting the availability of the SSH service.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS