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FreeBSDOperating system

CVE-2023-3326

CRITICAL · 9.8 CVSS v3.1 Published 2023-06-22
Fix available
A fix is available. Upgrade to 12.4 / 13.1 or later.
See remediation →
100/100
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
pam_krb5 authenticates a user by essentially running kinit with the password, getting a ticket-granting ticket (tgt) from the Kerberos KDC (Key Distribution Center) over the network, as a way to verify the password. However, if a keytab is not provisioned on the system, pam_krb5 has no way to validate the response from the KDC, and essentially trusts the tgt provided over the network as being valid. In a non-default FreeBSD installation that leverages pam_krb5 for authentication and does not have a keytab provisioned, an attacker that is able to control both the password and the KDC responses can return a valid tgt, allowing authentication to occur for any user on the system.

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 · high confidence

pam_krb5 authenticates users by obtaining a TGT from the Kerberos KDC. When no keytab is provisioned on the system, pam_krb5 cannot validate the KDC response and blindly trusts the TGT received over the network as valid. An attacker controlling both the password input and KDC responses can return a valid TGT to bypass authentication for any user.

MitigationProvision a keytab on systems using pam_krb5 to enable validation of KDC responses, or ensure the KDC is trusted and network communications are secured.

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
FreeBSDOperating system
Affected:< 12.4>= 13.0, < 13.1= 12.4= 13.1= 13.2

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
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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 if pam_krb5 is loaded in PAM configuration
    Inspect /etc/pam.d/ files for pam_krb5.so module entries, particularly in system-auth or login configuration
    Affected if pam_krb5.so is present in any PAM service configuration without a corresponding keytab present on the system
  2. Determine the FreeBSD version
    Run 'uname -r' or 'freebsd-version -k' to identify the installed FreeBSD release
    Affected if The version matches: < 12.4, 12.4, 13.0, 13.1, or 13.2
  3. Verify if a keytab file exists for KDC validation
    Check for the presence of a keytab file (commonly /etc/krb5.keytab or as defined in krb5.conf) using 'ls -la' or 'klist -k'
    Affected if No keytab file exists and the system relies on pam_krb5 for authentication

A system is affected if it runs a vulnerable FreeBSD version (12.4, 13.0, 13.1, or 13.2) with pam_krb5 configured in PAM without a provisioned keytab for KDC response validation.

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 12.4 / 13.1 or later
Fixed in 12.413.1
Interim mitigation

Provision a keytab on systems using pam_krb5 to enable validation of KDC responses, or ensure the KDC is trusted and network communications are secured.

Recommended fix Moderate confidence

FreeBSD 12.5+ or 13.2+ (latest stable release in respective branch)

  1. 1. Identify the current FreeBSD version using 'freebsd-version -u' or 'uname -a'
  2. 2. For systems running FreeBSD 12.x: Upgrade to FreeBSD 12.4-STABLE or later (12.5 or newer)
  3. 3. For systems running FreeBSD 13.x: Upgrade to FreeBSD 13.1-STABLE or later (13.2 or newer)
  4. 4. Back up all critical data and configuration files before performing the upgrade
  5. 5. Run 'freebsd-update fetch install' or rebuild world and kernel from source using 'make world' and 'make kernel'
  6. 6. After reboot, verify the new version using 'uname -a' and confirm the pam_krb5 package version is updated
Caveat Major FreeBSD upgrades (e.g., 12.x to 13.x) may require checking application compatibility; review /usr/UPDATING for any migration notes

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

Fix this in FreeBSD Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing3.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,490
Get the upgrade done

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Scan for this in your stack

Free · runs locally
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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-2023-3326 in production — separate from our analysis above.

No notes yet

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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