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Directory ServerApplication · Redhat

CVE-2026-11789

MEDIUM · 6.5 CVSS v3.1 Published 2026-06-09
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
71/100
Remediation priority · Elevated
Remotely reachable 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 389 Directory Server. The SMD5 password storage plugin performs unsigned integer underflow when computing salt length from a crafted password hash shorter than 16 bytes, causing a buffer over-read that crashes the LDAP server during authentication.

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 SMD5 password storage plugin in 389 Directory Server contains an unsigned integer underflow vulnerability when processing password hashes shorter than 16 bytes. The flaw occurs during salt length computation, where the short hash causes the integer to underflow, resulting in a buffer over-read that crashes the LDAP server during authentication attempts.

MitigationApply the vendor patch for CVE-2026-11789 to address the integer underflow in the SMD5 plugin. As a temporary mitigation, consider disabling the SMD5 password scheme and using a stronger hash algorithm if supported.

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
Directory ServerApplication
Affected:= 11.0= 12.0= 13.0
389 Directory ServerOperating system
Affected:all versions
Enterprise LinuxOperating system
Affected:= 7.0= 8.0= 9.0= 10.0

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
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/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 389 Directory Server version
    Run 'rpm -qa | grep 389-ds-base' or check the version via 'dsadm --version' if available. Alternatively, inspect /etc/dirsrv/slapd-<instance>/dse.ldif for 'nsVersion' attribute or query cn=snmp,cn=monitor via ldapsearch.
    Affected if The installed version matches Redhat Directory Server 11.0, 12.0, 13.0 or any version of Redhat 389 Directory Server (all versions affected).
  2. Confirm SMD5 password scheme is enabled in configuration
    Check the password storage scheme configuration. Run: 'ldapsearch -x -H ldap://localhost -D "cn=Directory Manager" -W -b "cn=config" "(objectClass=*)" nsslapd-passwordhash' or inspect /etc/dirsrv/slapd-<instance>/dse.ldif for 'nsslapd-passwordhash' attribute.
    Affected if The nsslapd-passwordhash configuration includes 'SMD5' among the allowed schemes.
  3. Identify user accounts using SMD5 password hashes
    Query userPassword attributes to detect SMD5-prefixed hashes. Run: 'ldapsearch -x -H ldap://localhost -D "cn=Directory Manager" -W -b "ou=people,dc=example,dc=com" "(objectClass=inetOrgPerson)" userPassword' and look for values starting with '{SMD5}'.
    Affected if Any user account has a password hash prefixed with '{SMD5}', indicating SMD5 scheme is in active use.
  4. Verify password hash length in stored SMD5 hashes
    If SMD5 hashes are found, inspect their base64-decoded length. SMD5 hashes should be 16 bytes; hashes shorter than 16 bytes (after decoding) trigger the underflow. Examine specific userPassword values: '{SMD5}...' and verify the raw hash length.
    Affected if Any stored SMD5 password hash is shorter than 16 bytes in raw binary form after base64 decoding.

A system is affected if it runs a vulnerable 389 Directory Server version, has SMD5 scheme enabled, and has at least one user account with an SMD5 password hash shorter than 16 bytes that could trigger the underflow during authentication.

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 vendor patch for CVE-2026-11789 to address the integer underflow in the SMD5 plugin. As a temporary mitigation, consider disabling the SMD5 password scheme and using a stronger hash algorithm if supported.

Fix this in Directory Server Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing8.0 h
  • Review / QA4.0 h
24.0 hours of engineering $4,160
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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-2026-11789 in production — separate from our analysis above.

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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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