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Hardened ImagesApplication · Redhat

CVE-2026-3184

MEDIUM · 5.3 CVSS v3.1 Published 2026-04-03
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
62/100
Remediation priority · Elevated
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 util-linux. Improper hostname canonicalization in the `login(1)` utility, when invoked with the `-h` option, can modify the supplied remote hostname before setting `PAM_RHOST`. A remote attacker could exploit this by providing a specially crafted hostname, potentially bypassing host-based Pluggable Authentication Modules (PAM) access control rules that rely on fully qualified domain names. This could lead to unauthorized access.

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 util-linux login(1) utility with the -h option performs improper hostname canonicalization, modifying the supplied remote hostname before passing it to PAM as PAM_RHOST. This allows attackers to bypass host-based PAM authentication rules that rely on fully qualified domain names by providing specially crafted hostnames.

MitigationApply the util-linux security patch when available. In the interim, review PAM rules that depend on PAM_RHOST for host-based access control and consider using multiple hostname formats or additional authentication factors.

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
Util LinuxApplication
Affected:all versions

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
None

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

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 if util-linux login is installed
    Run 'which login' and check package manager output with 'rpm -q util-linux' or 'dpkg -l util-linux'
    Affected if The login utility from util-linux package is present on the system
  2. Verify PAM configuration uses hostname-based access control
    Examine PAM configuration files for services using login (such as /etc/pam.d/login, /etc/pam.d/sshd, /etc/pam.d/remote) and look for pam_access, pam_time, or similar modules that evaluate the PAM_RHOST environment variable
    Affected if PAM rules reference client hostname (PAM_RHOST) for access control decisions
  3. Confirm remote authentication is enabled for login
    Check /etc/login.defs for ENABLE_REMOTE (or similar) settings and verify that services like SSH or remote access are configured to use the system login program
    Affected if The system allows remote connections that invoke the login program with -h option or via PAM_RHOST
  4. Test hostname handling in login
    Attempt a login attempt with a partially qualified hostname using 'login -h hostname' (if testing is safe in your environment) and observe how the hostname appears in PAM_RHOST
    Affected if The hostname gets modified/canonicalized differently than the input provided, indicating improper handling

A system is affected if it runs util-linux login and has PAM configurations that rely on PAM_RHOST for hostname-based access control, as the canonicalization flaw can allow hostname-based bypasses.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply the util-linux security patch when available. In the interim, review PAM rules that depend on PAM_RHOST for host-based access control and consider using multiple hostname formats or additional authentication factors.

Fix this in Hardened Images Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,930
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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-2026-3184 in production — separate from our analysis above.

No notes yet

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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