CVE-2026-59846: Shell Metacharacter Injection via %r ProxyCommand in libssh
CVE-2026-59846 Published on July 21, 2026
Libssh: libssh: information disclosure via proxycommand %r username expansion
A flaw was found in libssh. A malicious username expanded through %r in ProxyCommand handling can inject shell metacharacters, exposing environment variables and causing unintended shell behavior.
Vulnerability Analysis
CVE-2026-59846 is exploitable with local system access, requires user interaction and a small amount of user privileges. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have a small impact on confidentiality and integrity, and no impact on availability.
Timeline
Reported to Red Hat.
Made public. 83 days later.
Weakness Types
What is a Shell injection Vulnerability?
The software constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component.
CVE-2026-59846 has been classified to as a Shell injection vulnerability or weakness.
What is a Command Injection Vulnerability?
The software constructs all or part of a command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended command when it is sent to a downstream component.
CVE-2026-59846 has been classified to as a Command Injection vulnerability or weakness.
Products Associated with CVE-2026-59846
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Affected Versions
Red Hat Enterprise Linux 10:- Version 0:0.12.0-3.el10_2 and below * is unaffected.
- Version 0.12.1-4.hum1 and below * is unaffected.