CVE-2026-59851 (GCVE-0-2026-59851)

Vulnerability from cvelistv5 – Published: 2026-07-21 14:20 – Updated: 2026-08-17 21:38
VLAI
Title
Libssh: libssh: authentication bypass via missing gssapi principal check
Summary
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.
Severity
8.8 (High)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
SSVC
Exploitation: none Automatable: no Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-07-22 18:14 UTC
CWE
  • CWE-863 - Incorrect Authorization
Assigner
References
URL Tags
https://access.redhat.com/errata/RHSA-2026:42922 vendor-advisoryx_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:55855 vendor-advisoryx_refsource_REDHAT
https://access.redhat.com/security/cve/CVE-2026-59851 vdb-entryx_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2498184 issue-trackingx_refsource_REDHAT
Impacted products
Vendor Product Version CPE status
Red Hat Red Hat Enterprise Linux 10 Unaffected: 0:0.12.0-3.el10_2 , < * (rpm)
    cpe:/o:redhat:enterprise_linux:10.2
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Red Hat Red Hat Hardened Images Unaffected: 0.12.1-4.hum1 , < * (rpm)
    cpe:/a:redhat:hummingbird:1
Create a notification for this product.
Red Hat Red Hat Enterprise Linux 8     cpe:/o:redhat:enterprise_linux:8
Create a notification for this product.
Red Hat Red Hat Enterprise Linux 9     cpe:/o:redhat:enterprise_linux:9
Create a notification for this product.
Date Public
2026-07-21 14:14
Credits
Red Hat would like to thank Aisle Research for reporting this issue.
Show details on NVD website
To clipboard 

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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.


Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.