Directory ServerApplication · Redhat
CVE-2026-11787
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 · uneditedA flaw was found in 389 Directory Server. The ldap_utf8prev() function reads bytes before the start of a buffer without bounds checking, causing a heap buffer over-read in string filter parsing that may influence internal filter processing behavior.
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 confidence389 Directory Server contains a heap buffer over-read vulnerability in the ldap_utf8prev() function, which lacks bounds checking when reading bytes before the start of a buffer during string filter parsing. This flaw could allow an attacker to influence internal filter processing behavior through specially crafted LDAP filter inputs.
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
= 11.0= 12.0= 13.0
389 Directory ServerOperating system
all versions
Enterprise LinuxOperating system
= 7.0= 8.0= 9.0= 10.0CVSS 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
- Low
- Integrity
- Low
- Availability
- Low
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
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 checksWork through these to decide whether this CVE applies to you.
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Identify if 389 Directory Server packages are installedRun 'rpm -qa | grep -E "(389-ds-base|dirserver)"' to list installed 389 Directory Server related packagesAffected if No 389 Directory Server packages are found, the system is not affected by this CVE
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Determine the installed 389 Directory Server versionRun 'rpm -q --qf "%{VERSION}-%{RELEASE}" <package-name>' for the package found in step 1, or check 'rpm -qi 389-ds-base' for full version detailsAffected if The version matches Red Hat Directory Server 11.0, 12.0, or 13.0, or any version of 389-ds-base package (all versions are affected)
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Check if the directory server service is runningRun 'systemctl status dirsrv' or 'ps aux | grep ns-slapd' to verify the Directory Server daemon is activeAffected if The service is running and version is vulnerable per step 2, the system is potentially exploitable through LDAP filter operations
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Confirm the underlying RHEL versionRun 'cat /etc/redhat-release' to check the Red Hat Enterprise Linux versionAffected if Running RHEL 7.0, 8.0, 9.0, or 10.0 with 389 Directory Server installed, the environment falls within the affected scope
The environment is affected if 389 Directory Server (or Red Hat Directory Server) is installed and the installed version is 11.0, 12.0, 13.0, or any version of the 389-ds-base package on RHEL 7.0-10.0.
Generated from the published advisory. Verify against your own configuration.
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 dataApply the vendor patch for CVE-2026-11787 which adds proper bounds checking to the ldap_utf8prev() function in the LDAP filter parsing code.
Fix this in Directory Server
Scoped from the published advisory
- Consultation2.0 h
- Implementation3.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,800.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-11787 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-11787 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- 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
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