CVE-2026-59851 Details
Description
A flaw was found in libssh. On servers with GSSAPIKeyExchange enabled, the gssapi-keyex path does not verify whether the authenticated Kerberos principal is authorized for the requested local user, allowing authenticated clients to log in as arbitrary users.
An authentication bypass vulnerability has been identified in libssh on servers with GSSAPIKeyExchange enabled. The issue arises because the gssapi-keyex login path does not verify if the authenticated Kerberos principal is authorized for the requested local user. This flaw allows authenticated clients to log in as arbitrary users.
To address this vulnerability, GSSAPIKeyExchange should be disabled on the server.
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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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://access.redhat.com/errata/RHSA-2026:42922 | [email protected] | Issue Tracking |
| https://access.redhat.com/errata/RHSA-2026:55855 | [email protected] | |
| https://access.redhat.com/security/cve/CVE-2026-59851 | [email protected] | Vendor Advisory |
| https://bugzilla.redhat.com/show_bug.cgi?id=2498184 | [email protected] | Issue TrackingVendor Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-863 | Incorrect Authorization | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| libssh libssh | All versions |
CPE
Remediation
| |
| redhat hardened images | All versions |
CPE
Remediation
| |
| redhat enterprise linux | 10.0 |
CPE
Remediation
| |
Change History
6 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Aug 17, 2026 | CVE Modified | [email protected] |
| Jul 30, 2026 | Initial Analysis | [email protected] |
| Jul 22, 2026 | CVE Modified | [email protected] |
| Jul 22, 2026 | CVE Modified | CISA-ADP |
| Jul 21, 2026 | CVE Modified | [email protected] |
| Jul 21, 2026 | New CVE Received | [email protected] |