dbcve.org
Enterprise LinuxOperating system · Redhat

CVE-2026-0967

MEDIUM · 5.5 CVSS v3.1 Published 2026-03-26
Fix available
A fix is available. Upgrade to after 0.11.3 or later.
See remediation →
58/100
Remediation priority · Elevated
No privileges

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. A remote attacker, by controlling client configuration files or known_hosts files, could craft specific hostnames that when processed by the `match_pattern()` function can lead to inefficient regular expression backtracking. This can cause timeouts and resource exhaustion, resulting in a Denial of Service (DoS) for the client.

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

libssh contains a Regular Expression Denial of Service (ReDoS) vulnerability in the match_pattern() function. A remote attacker who can control client configuration files or known_hosts files can craft specific hostnames that trigger inefficient regex backtracking, causing excessive CPU consumption, timeouts, and resource exhaustion on the client.

MitigationAvoid using client configuration files or known_hosts files from untrusted sources. Update libssh to the latest version once a patch is available. Consider implementing timeout limits on pattern matching operations as a defense-in-depth measure.

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
Enterprise LinuxOperating system
Affected:= 9.0= 10.0
LibsshApplication
Affected:<= 0.11.3

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
Local
Complexity
Low
Privileges
None
User interaction
Required
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/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. Identify installed libssh version
    Run 'rpm -q libssh' on RHEL systems, or 'ssh -V' / check library version with 'ldd' or package manager on other systems
    Affected if The installed version is libssh <= 0.11.3, or the system is RHEL 9.0 or RHEL 10.0 with libssh installed
  2. Locate client configuration files
    Check for the presence of ~/.ssh/config and ~/.ssh/known_hosts files in user home directories
    Affected if These files exist and are used by the SSH client for host pattern matching
  3. Check file permissions and sources
    Inspect file ownership and permissions of ~/.ssh/config and ~/.ssh/known_hosts using 'ls -la ~/.ssh/'
    Affected if Files are writable by untrusted users or were imported from untrusted sources
  4. Verify pattern matching usage
    Review SSH config files for Host or Match directives that use pattern matching against hostnames
    Affected if Pattern matching directives are present in client configuration files
  5. Assess risk from untrusted sources
    Determine if known_hosts or config files could contain entries from untrusted or compromised servers
    Affected if The system has ever connected to untrusted hosts or imported known_hosts from external sources

A user is affected if they have libssh version 0.11.3 or earlier (or are on RHEL 9.0/10.0 with libssh installed) AND use client configuration files or known_hosts that could contain attacker-controlled hostnames with regex patterns triggering inefficient backtracking.

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 a release after 0.11.3
Interim mitigation

Avoid using client configuration files or known_hosts files from untrusted sources. Update libssh to the latest version once a patch is available. Consider implementing timeout limits on pattern matching operations as a defense-in-depth measure.

Recommended fix Moderate confidence

libssh > 0.11.3 (check Red Hat errata for exact fixed version)

  1. Run `dnf check-update libssh` or `yum update libssh` to check for available security updates
  2. If an update is available, run `dnf update libssh` or `yum update libssh` to apply the fix
  3. Alternatively, verify the current version with `rpm -q libssh` and confirm it is newer than 0.11.3 after updating
  4. Restart any SSH services or applications using libssh to ensure the patched library is loaded

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

Fix this in Enterprise Linux Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA3.0 h
21.0 hours of engineering $3,680
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Scan for this in your stack

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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-2026-0967 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