A flaw was found in libssh. On servers with GSSAPIKeyExchange enabled, the gssapi-keyex path does not verify whether the authenticated Kerberos… (CVE-2026-59851)
A vulnerability in libssh affects servers with GSSAPIKeyExchange enabled, where the gssapi-keyex authentication path fails to verify if the authenticated Kerberos principal is authorized for the requested local user. This flaw allows authenticated clients to log in as arbitrary users without proper authorization checks. The issue is tracked as CVE-2026-59851 and has a high severity score of 8.8. Red Hat has released security updates addressing this vulnerability in their Hardened Images and Red Hat Enterprise Linux 10 packages.
AI Analysis
Technical Summary
CVE-2026-59851 is an authentication bypass vulnerability in libssh occurring when GSSAPIKeyExchange is enabled. The gssapi-keyex path does not verify whether the authenticated Kerberos principal is authorized for the requested local user, enabling authenticated clients to impersonate arbitrary users. This is classified under CWE-863 (Incorrect Authorization). Red Hat advisories RHSA-2026:42922 and RHSA-2026:55855 provide updated libssh packages that fix this issue among other vulnerabilities.
Potential Impact
Successful exploitation allows an authenticated client to bypass authorization checks and log in as any local user on the server, potentially leading to full system compromise. The CVSS v3.1 score of 8.8 reflects high impact on confidentiality, integrity, and availability.
Mitigation Recommendations
Red Hat has issued official security updates that fix this vulnerability. Users of affected Red Hat Hardened Images and Red Hat Enterprise Linux 10 should apply the updated libssh packages (e.g., libssh-0.12.1-4.hum1 and libssh-0.12.0-3.el10_2) as soon as possible. Refer to Red Hat advisories RHSA-2026:42922 and RHSA-2026:55855 for detailed update instructions. No additional mitigations are required beyond applying the official patches.
A flaw was found in libssh. On servers with GSSAPIKeyExchange enabled, the gssapi-keyex path does not verify whether the authenticated Kerberos… (CVE-2026-59851)
Description
A vulnerability in libssh affects servers with GSSAPIKeyExchange enabled, where the gssapi-keyex authentication path fails to verify if the authenticated Kerberos principal is authorized for the requested local user. This flaw allows authenticated clients to log in as arbitrary users without proper authorization checks. The issue is tracked as CVE-2026-59851 and has a high severity score of 8.8. Red Hat has released security updates addressing this vulnerability in their Hardened Images and Red Hat Enterprise Linux 10 packages.
CVSS v3.1
Score 8.8high
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-59851 is an authentication bypass vulnerability in libssh occurring when GSSAPIKeyExchange is enabled. The gssapi-keyex path does not verify whether the authenticated Kerberos principal is authorized for the requested local user, enabling authenticated clients to impersonate arbitrary users. This is classified under CWE-863 (Incorrect Authorization). Red Hat advisories RHSA-2026:42922 and RHSA-2026:55855 provide updated libssh packages that fix this issue among other vulnerabilities.
Potential Impact
Successful exploitation allows an authenticated client to bypass authorization checks and log in as any local user on the server, potentially leading to full system compromise. The CVSS v3.1 score of 8.8 reflects high impact on confidentiality, integrity, and availability.
Mitigation Recommendations
Red Hat has issued official security updates that fix this vulnerability. Users of affected Red Hat Hardened Images and Red Hat Enterprise Linux 10 should apply the updated libssh packages (e.g., libssh-0.12.1-4.hum1 and libssh-0.12.0-3.el10_2) as soon as possible. Refer to Red Hat advisories RHSA-2026:42922 and RHSA-2026:55855 for detailed update instructions. No additional mitigations are required beyond applying the official patches.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-x5cr-v39m-53gw
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2026-59851"]
- Ecosystems
- []
- Database Specific Severity
- HIGH
- Cvss Version
- 3.1
Patch Information
Threat ID: 6a83aa7dbf8831d539e32b02
Added to database: 08/18/2026, 00:42:37 UTC
Last enriched: 08/18/2026, 00:57:58 UTC
Last updated: 08/18/2026, 01:21:08 UTC
Views: 2
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