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No exploitation reportedFix available

CVE-2026-0966

Libssh: libssh: denial of service via zero-length input in ssh_get_hexa()

No exploitation reported by the sources we read.

  • Published2026-03-26
  • Fixed in0.11.4
  • WeaknessCWE-124

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. The API function `ssh_get_hexa()` is vulnerable to a denial of service when processing zero-length input. This can be exploited remotely by an attacker during GSSAPI (Generic Security Service Application Program Interface) authentication if the server's logging verbosity is set to `SSH_LOG_PACKET (3)` or higher. Successful exploitation could lead to a self-Denial of Service of the per-connection daemon process.

Timeline

dates in UTC
  1. 2026-03-2620:06CVE publishedCNA

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-2026-0966?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-0966?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
0.11< 0.11.40.11.4
Redhat enterprise linux
BranchAffectedFixed in
8.0= 8.0no fix published
9.0= 9.0no fix published
10.0= 10.0no fix published
Redhat hardened images
BranchAffectedFixed in
—all versionsno fix published

1 more product in the sources.

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

Products declared by the CNA9 products

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

3 more products in the CVE record.

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2026-09-01

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

  • libsshUbuntu:Pro:20.04:LTSall versions · fixed in 0.9.3-2ubuntu2.5+esm3
  • libsshUbuntu:Pro:18.04:LTSall versions · fixed in 0.8.0~20170825.94fa1e38-1ubuntu0.7+esm6
  • libsshUbuntu:Pro:16.04:LTSall versions · fixed in 0.6.3-4.3ubuntu0.6+esm4
  • libsshUbuntu:25.10all versions · fixed in 0.11.2-1ubuntu0.2
  • libsshUbuntu:24.04:LTSall versions · fixed in 0.10.6-2ubuntu0.3
  • libsshUbuntu:22.04:LTSall versions · fixed in 0.9.6-2ubuntu0.22.04.6
  • libsshTuxCare:CentOS:8.5all versions · fixed in 0.9.4-3.el8.tuxcare.els9and 2 other packages
  • libsshTuxCare:CentOS:8.4all versions · fixed in 0.9.4-3.el8.tuxcare.els9and 2 other packages

43 more package ranges on OSV.dev

Vendor advisories

  • CVE-2026-0966 Red Hat Product Security65 products fixed · 6 known affected

    libssh: libssh: Denial of Service via zero-length input in ssh_get_hexa()

    libssh as a component of Red Hat Enterprise Linux 8 · libssh-config as a component of Red Hat Enterprise Linux 8 · libssh-devel as a component of Red Hat Enterprise Linux 8 · +3 more

  • RHSA-2026:18683 Red Hat Product Security32 products fixed

    Red Hat Security Advisory: libssh security update

  • RHSA-2026:18160 Red Hat Product Security26 products fixed

    Red Hat Security Advisory: libssh security update

  • RHSA-2026:7067 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. Update Libssh to 0.11.4
  2. Vendor fix Red Hat Product Security RHSA-2026:18683 · 32 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
  3. Vendor fix Red Hat Product Security RHSA-2026:7067 · 7 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://images.redhat.com/
  4. Workaround from the vendor Red Hat Product Security RHSA-2026:18683 · 32 productsApplications using libssh should avoid passing zero-length input to ssh_get_hexa(), ssh_get_fingerprint_hash(), and ssh_print_hexa(). For the remotely reachable GSSAPI authentication path, disable GSSAPI authentication in the affected libssh-based application if it is not required, or configure th…
  5. No fix available, says the vendor Red Hat Product Security CVE-2026-0966 · 6 productsFix deferred

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:N/UI:N/S:U/C:N/I:L/A:H
Published
2026-03-26
Last Modified
2026-09-01
NVD status
Modified
GitHub Advisory
GHSA-wcqf-w94x-4wg2

Frequently asked questions

What is CVE-2026-0966?

A flaw was found in libssh. The API function `ssh_get_hexa()` is vulnerable to a denial of service when processing zero-length input. This can be exploited remotely by an attacker during GSSAPI (Generic Security Service Application Program Interface) authentication if the server's logging verbosity is set to `SSH_LOG_PACKET (3)` or higher. Successful exploitation could lead to a self-Denial of Service of the per-connection daemon process.

Is CVE-2026-0966 actively exploited?

Active exploitation of CVE-2026-0966 has not been confirmed. Its EPSS score was 0.6% on 2026-11-03, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-0966?

CVE-2026-0966 has a CVSS v3 base score of 8.2 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H.

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