High severity · published Jul 21, 2026
CVE-2026-59851
Libssh: libssh: authentication bypass via missing gssapi principal check
8.8
CVSS
0.5%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 42% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
RH
Red Hat Enterprise Linux 10 · Red Hat
All versions, or not specified · source: vendor
RH
Red Hat Hardened Images · Red Hat
All versions, or not specified · source: vendor
EL
Enterprise Linux · Redhat
10.0 · source: NVD
HI
Hardened Images · Redhat
All versions, or not specified · source: NVD
LI
Libssh · Libssh
All versions, or not specified · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-59851
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-59851
Issue Tracking
https://access.redhat.com/errata/RHSA-2026:42922
access.redhat.com
https://access.redhat.com/errata/RHSA-2026:55855
Vendor Advisory
https://access.redhat.com/security/cve/CVE-2026-59851
Issue Tracking
https://bugzilla.redhat.com/show_bug.cgi?id=2498184
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