CVE-2026-59846 Details
Description
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.
A vulnerability exists in libssh's handling of usernames within ProxyCommand expansions. The issue arises because the validation process for usernames does not adequately filter out characters that could be interpreted by the shell. This flaw allows malicious usernames to inject shell metacharacters, which can then be evaluated by the shell. As a result, sensitive environment variables may be exposed, and unintended shell behaviors could occur. This vulnerability affects libssh in Red Hat Enterprise Linux 8, 9, and 10, as well as Red Hat Hardened Images.
Users are advised to avoid using untrusted usernames that could be exploited to inject shell metacharacters in ProxyCommand expansions.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Jul 22, 2026References to Advisories, Solutions, and Tools
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Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-77 | Improper Neutralization of Special Elements used in a Command ('Command Injection') | CISA-ADP |
| CWE-78 | Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| libssh libssh | All versions |
CPE
Remediation
| |
| redhat hardened images | All versions |
CPE
Remediation
| |
| redhat enterprise linux | 8.0 9.0 10.0 |
CPE
Remediation
| |
Change History
9 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Sep 1, 2026 | CVE Modified | [email protected] |
| Sep 1, 2026 | CVE Modified | [email protected] |
| Aug 19, 2026 | CVE Modified | [email protected] |
| Aug 12, 2026 | CVE Modified | [email protected] |
| Jul 30, 2026 | Initial Analysis | [email protected] |
| Jul 23, 2026 | CVE Modified | CISA-ADP |
| Jul 22, 2026 | CVE Modified | [email protected] |
| Jul 22, 2026 | CVE Modified | CISA-ADP |
| Jul 21, 2026 | New CVE Received | [email protected] |