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Hardened ImagesApplication · Redhat

CVE-2026-0966

HIGH · 8.2 CVSS v3.1 Published 2026-03-26
Fix available
A fix is available. Upgrade to 0.11.4 or later.
See remediation →
91/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

The libssh function `ssh_get_hexa()` crashes when processing zero-length input under high verbosity logging (SSH_LOG_PACKET 3+). This triggers during GSSAPI authentication, causing the per-connection daemon process to self-terminate from a denial of service condition.

MitigationUntil a patch is available, reduce logging verbosity below SSH_LOG_PACKET level 3 as a workaround, or upgrade libssh once the vendor releases an official fix.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Hardened ImagesApplication
Affected:all versions
Openshift Container PlatformApplication
Affected:= 4.0
Enterprise LinuxOperating system
Affected:= 8.0= 9.0= 10.0
LibsshApplication
Affected:< 0.11.4

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check installed libssh version
    Run `rpm -q libssh` or `dpkg -l libssh` to identify the installed package version, or check the library directly via `ssh -V` or by inspecting the library file.
    Affected if The version is lower than 0.11.4 (for upstream libssh) or on Redhat Enterprise Linux 8.0, 9.0, or 10.0 without the vendor patch.
  2. Verify GSSAPI authentication is enabled
    Inspect the SSH daemon configuration file (typically /etc/ssh/sshd_config) for the `GSSAPIAuthentication` directive or check if GSSAPI is listed in the enabled authentication methods.
    Affected if GSSAPIAuthentication is set to yes (the default in some configurations).
  3. Check SSH logging verbosity level
    Inspect the SSH daemon configuration for the `LogLevel` directive, or check runtime configuration via sshd -T. Look for LogLevel set to PACKET, DEBUG, or DEBUG2/DEBUG3.
    Affected if LogLevel is set to PACKET, DEBUG, DEBUG2, or DEBUG3 (equivalent to value 3 or higher).
  4. Confirm the vulnerable code path is reachable
    Verify that both GSSAPI authentication is enabled AND logging verbosity is SSH_LOG_PACKET (3) or higher. These two conditions must both be true for the vulnerability to be exploitable.
    Affected if Both conditions are true: GSSAPI auth enabled AND verbosity level 3 or higher.

You are affected if your libssh version is vulnerable (below 0.11.4 or on the listed Redhat versions) AND both GSSAPI authentication is enabled AND logging verbosity is set to SSH_LOG_PACKET (3) or higher.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 0.11.4 or later
Fixed in 0.11.4
Interim mitigation

Until a patch is available, reduce logging verbosity below SSH_LOG_PACKET level 3 as a workaround, or upgrade libssh once the vendor releases an official fix.

Recommended fix High confidence

libssh 0.11.4

  1. 1. Identify all systems running libssh versions prior to 0.11.4
  2. 2. For RHEL/CentOS systems: run `sudo dnf check-update` or `sudo yum check-update` to check for available libssh updates
  3. 3. For RHEL/CentOS systems: run `sudo dnf update libssh` or `sudo yum update libssh` to apply the security update
  4. 4. For other Linux distributions: use the system package manager to update libssh to version 0.11.4 or later
  5. 5. For embedded systems or custom builds: download libssh 0.11.4 or later from www.libssh.org and rebuild/redeploy
  6. 6. After updating, restart any SSH services that link against libssh to load the fixed library
  7. 7. Verify the installed version using `ssh -V` or by checking the library file directly

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Hardened Images Scoped from the published advisory
  • Consultation4.0 h
  • Implementation2.0 h
  • Testing6.0 h
  • Review / QA3.0 h
15.0 hours of engineering $2,600
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-0966 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data