libssh Configuration and Protocol Flaws

Remote denial-of-service in libssh 0.11.x and earlier allows unauthenticated attackers to crash SSH server daemon processes via malformed GSSAPI authentication OID payloads. The vulnerability affects the ssh_get_hexa() API function when processing zero-length input, exploitable remotely when GSSAPI authentication is enabled and logging verbosity is set to SSH_LOG_PATCH (level 3) or higher. Red Hat, Ubuntu, SUSE, and Debian have released patches (libssh 0.11.4 and 0.12.0). EPSS score of 0.09% and SSVC assessment indicate low real-world exploitation likelihood despite network attack vector, with no active exploitation confirmed. Ubuntu classified this as low priority, and CISA SSVC notes exploitation as 'none' but 'automatable' with partial impact.

libssh's match_pattern() function is vulnerable to ReDoS (Regular Expression Denial of Service) attacks when processing maliciously crafted hostnames in client configuration or known_hosts files, allowing local attackers with limited privileges and user interaction to trigger inefficient regex backtracking that exhausts system resources and causes client-side timeouts. The vulnerability affects Red Hat Enterprise Linux 6-10 and OpenShift Container Platform 4, with CVSS 2.2 reflecting low severity due to local attack vector and high complexity requirements, though the denial of service impact warrants attention in environments where SSH client availability is critical.

Grafana OSS provisioning contact points API fails to enforce the alert.notifications.receivers.protected:write permission, allowing users with the Editor role to modify protected webhook URLs and bypass intended authorization controls. This affects Grafana OSS versions 11.6.9 through 11.6.14, 12.1.5 through 12.1.10, 12.2.2 through 12.2.8, and 12.3.1 through 12.3.6. Authenticated Editor-level users can exploit this to reconfigure webhook destinations, potentially redirecting alert notifications to attacker-controlled endpoints. No public exploit identified at time of analysis.

libssh attempts to open arbitrary files during configuration parsing, allowing local attackers with limited privileges to trigger a denial of service by forcing access to dangerous files such as block devices or large system files. The vulnerability affects Red Hat Enterprise Linux versions 6, 7, 8, 9, and 10, as well as Red Hat OpenShift Container Platform 4, and requires local access with low privileges to exploit. No public exploit code or active exploitation has been confirmed at the time of analysis.

Libssh versions used across Red Hat Enterprise Linux 6-10 and OpenShift Container Platform 4 are vulnerable to a null pointer dereference when processing malformed 'longname' fields in SFTP SSH_FXP_NAME messages, allowing unauthenticated remote attackers to trigger denial of service through application crashes. The attack requires user interaction and high attack complexity (CVSS 3.1, CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:L) but affects a widely deployed SSH library; no public exploit identified at time of analysis.