CVE-2026-59851

Libssh: libssh: authentication bypass via missing gssapi principal check

Published Jul 21, 2026 CVSS 3.1 · 8.8 High EPSS < 1% KEV · Not listed
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.

Remediation

Vendor Workaround

Disable GSSAPIKeyExchange.

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Redhat enterprise Linux Eus
Redhat enterprise Linux For Els
Redhat enterprise Linux For Ibm Z Systems
Redhat enterprise Linux For Ibm Z Systems Els
Redhat enterprise Linux For Ibm Z Systems Eus
Redhat enterprise Linux For Power Little Endian
Redhat enterprise Linux For Power Little Endian Els
Redhat enterprise Linux For Power Little Endian Eus
CPEs cpe:2.3:a:libssh:libssh:-:*:*:*:*:*:*:* cpe:2.3:a:libssh:libssh:0.12.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux:10.0:*:*:*:*:*:arm64:*
cpe:2.3:o:redhat:enterprise_linux:10.0:*:*:*:*:*:x86:*
cpe:2.3:o:redhat:enterprise_linux:10.2:*:*:*:*:*:arm64:*
cpe:2.3:o:redhat:enterprise_linux:10.2:*:*:*:*:*:x86:*
cpe:2.3:o:redhat:enterprise_linux_eus:10.2:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_eus:10.2:*:*:*:*:*:arm64:*
cpe:2.3:o:redhat:enterprise_linux_for_els:10.2:*:*:*:*:*:arm64:*
cpe:2.3:o:redhat:enterprise_linux_for_els:10.2:*:*:*:*:*:x64:*
cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems:10.0_s390x:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems:10.2:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems_els:10.2:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems_eus:10.2:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian:10.0_ppc64le:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian:10.2:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian_els:10.2:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian_eus:10.2:*:*:*:*:*:*:*
Vendors & Products Redhat enterprise Linux Eus
Redhat enterprise Linux For Els
Redhat enterprise Linux For Ibm Z Systems
Redhat enterprise Linux For Ibm Z Systems Els
Redhat enterprise Linux For Ibm Z Systems Eus
Redhat enterprise Linux For Power Little Endian
Redhat enterprise Linux For Power Little Endian Els
Redhat enterprise Linux For Power Little Endian Eus
Type Values Removed Values Added
CPEs cpe:/o:redhat:enterprise_linux:8
cpe:/o:redhat:enterprise_linux:9
cpe:/a:redhat:enterprise_linux:8
cpe:/a:redhat:enterprise_linux:9
Type Values Removed Values Added
CPEs cpe:/o:redhat:enterprise_linux:10 cpe:/o:redhat:enterprise_linux:10.2
References
Type Values Removed Values Added
First Time appeared Libssh
Libssh libssh
Redhat hardened Images
Vendors & Products Libssh
Libssh libssh
Redhat hardened Images
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
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.
Title Libssh: libssh: authentication bypass via missing gssapi principal check
First Time appeared Redhat
Redhat enterprise Linux
Redhat hummingbird
Weaknesses CWE-863
CPEs cpe:/a:redhat:hummingbird:1
cpe:/o:redhat:enterprise_linux:10
cpe:/o:redhat:enterprise_linux:8
cpe:/o:redhat:enterprise_linux:9
Vendors & Products Redhat
Redhat enterprise Linux
Redhat hummingbird
References
Metrics cvssV3_1

{'score': 8.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'}