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Heap-based Buffer OverflowWeakness · CWE-122

CVE-2026-11884

MEDIUM · 6.5 CVSS v3.1 Published 2026-06-10
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 heap buffer overflow flaw was found in 389 Directory Server. When serializing objectclass definitions, the oc_superior (SUP) field length is omitted from buffer size calculations in read_schema_dse() and schema_oc_to_string(), but the field is still written via strcat(). An attacker with Directory Manager privileges, or a compromised replication supplier, can trigger a server crash by creating objectclasses with long SUP values. This is an incomplete fix variant of CVE-2025-14905.

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

A heap buffer overflow vulnerability exists in 389 Directory Server's objectclass serialization functions read_schema_dse() and schema_oc_to_string(). When serializing objectclass definitions, the code calculates buffer size but omits the oc_superior (SUP) field length, yet still writes this field using strcat(), leading to overflow when long SUP values are present.

MitigationApply the complete fix for the buffer size calculation vulnerability in the affected serialization functions, ensuring the SUP field length is included in all buffer allocation calculations. Consider upgrading to the latest 389 Directory Server version if available, as this is an incomplete fix of CVE-2025-14905.

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

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

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/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. Verify 389 Directory Server is installed
    Check for the 389-ds-base package using 'rpm -qa | grep 389-ds-base' or 'dpkg -l | grep 389-ds-base'
    Affected if The package is not installed or not present
  2. Determine installed version of 389 Directory Server
    Run 'rpm -q 389-ds-base' or 'dpkg -s 389-ds-base' to get the version number, then compare against the affected version range for this vulnerability
    Affected if The installed version falls within the vulnerable version range and has not been patched
  3. Identify schema files containing objectclass definitions with SUP values
    Examine schema files in /etc/dirsrv/slapd-*/schema/ for objectclass definitions containing the 'SUP' keyword
    Affected if Schema files contain objectclass definitions with long or complex SUP values that could trigger the overflow during serialization
  4. Check if schema modification operations are permitted
    Review the server configuration in /etc/dirsrv/slapd-*/dse.ldif for 'nsslapd-allow-schema-modifications' setting or check via ldapsearch for cn=schema,cn=config
    Affected if Schema modifications are enabled and the server processes objectclass serialization routines (read_schema_dse or schema_oc_to_string)
  5. Verify the server is running and accessible for schema operations
    Use 'ldapsearch -x -H ldap://localhost:389 -D "cn=directory manager" -W -b "cn=schema,cn=config" objectClasses' to retrieve current schema objectClasses
    Affected if The server is running and returns objectclass definitions with SUP values during normal operations

A user is affected if 389 Directory Server is installed with a version within the vulnerable range AND the server processes objectclass definitions containing SUP values during schema serialization operations.

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 complete fix for the buffer size calculation vulnerability in the affected serialization functions, ensuring the SUP field length is included in all buffer allocation calculations. Consider upgrading to the latest 389 Directory Server version if available, as this is an incomplete fix of CVE-2025-14905.

Have this fixed Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing5.0 h
  • Review / QA3.0 h
17.0 hours of engineering $2,970
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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-2026-11884 in production — separate from our analysis above.

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What this is

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