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No exploitation reportedFix available

CVE-2026-59851

No exploitation reported by the sources we read.

  • Published2026-07-21
  • WeaknessCWE-863

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC
  1. 2026-07-2115:16CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-11-03 21:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-59851?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-59851?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Libssh
BranchAffectedFixed in
—all versionsno fix published
Redhat enterprise linux
BranchAffectedFixed in
10.0= 10.0no fix published
Redhat hardened images
BranchAffectedFixed in
—all versionsno fix published

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Products declared by the CNA4 products

As redhat, the CNA that assigned this CVE, declared them in the CVE record; versions as written.

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2026-08-17

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • libsshWolfiall versions · fixed in 0.12.1-r0and 1 other package
  • libsshRocky Linux:10all versions · fixed in 0:0.12.0-3.el10_2
  • libsshRed Hat:hummingbird:1all versions · fixed in 0:0.12.1-4.hum1and 2 other packages
  • libsshRed Hat:enterprise_linux:10.2all versions · fixed in 0:0.12.0-3.el10_2and 4 other packages
  • libsshDebian:14all versions · fixed in 0.12.1-1
  • libsshChainguardall versions · fixed in 0.12.1-r0and 1 other package
  • libsshAlpine:v3.24all versions · fixed in 0.12.1-r0
  • libsshAlpaquita:streamfrom 0.9.6-r1 · fixed in 0.12.1-r0

3 more package ranges on OSV.dev

Vendor advisories

  • CVE-2026-59851 Red Hat Product Security30 products fixed

    libssh: libssh: authentication bypass via missing GSSAPI principal check

  • RHSA-2026:55855 Red Hat Product Security26 products fixed

    Red Hat Security Advisory: libssh security update

  • RHSA-2026:42922 Red Hat Product Security7 products fixed

    Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update

Full record on NVD

Fix

  1. Vendor fix Red Hat Product Security RHSA-2026:55855 · 26 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
  2. Vendor fix Red Hat Product Security RHSA-2026:42922 · 7 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://images.redhat.com/
  3. Workaround from the vendor Red Hat Product Security RHSA-2026:55855 · 26 productsDisable GSSAPIKeyExchange.

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub
Metasploit modules
none listed
Metasploit Framework

Sources

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Published
2026-07-21
Last Modified
2026-08-17
NVD status
Modified
GitHub Advisory
GHSA-x5cr-v39m-53gw

Frequently asked questions

What is CVE-2026-59851?

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.

Is CVE-2026-59851 actively exploited?

Active exploitation of CVE-2026-59851 has not been confirmed. Its EPSS score was 0.5% on 2026-11-03, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-59851?

CVE-2026-59851 has a CVSS v3 base score of 8.8 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

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Sources for this record