Local DoS via unchecked fork() in libssh ProxyCommand
CVE-2026-59845 Published on July 21, 2026

Libssh: libssh: denial of service via unchecked proxycommand fork() failure
A flaw was found in libssh. When ProxyCommand is used, an unchecked fork() failure can be stored as process ID -1; during cleanup, signals may then be sent across the caller's accessible process tree, leading to local denial of service.

Vendor Advisory Vendor Advisory NVD

Vulnerability Analysis

CVE-2026-59845 can be exploited with local system access, requires user interaction and a small amount of user privileges. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a high impact on availability.

Attack Vector:
LOCAL
Attack Complexity:
HIGH
Privileges Required:
LOW
User Interaction:
REQUIRED
Scope:
CHANGED
Confidentiality Impact:
NONE
Integrity Impact:
NONE
Availability Impact:
HIGH

Timeline

Reported to Red Hat.

Made public. 83 days later.

Weakness Type

Detection of Error Condition Without Action

The software detects a specific error, but takes no actions to handle the error.


Products Associated with CVE-2026-59845

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Red Hat Enterprise Linux (RHEL)
 
Red Hat Hummingbird
 

Affected Versions

Red Hat Enterprise Linux 10: Red Hat Hardened Images: Red Hat Enterprise Linux 8: Red Hat Enterprise Linux 9: