Filter misparsing via out-of-bounds UTF-8 read
Published Jun 9, 2026 · Updated Jun 9, 2026
Heap buffer over-read in Red Hat Directory Server allows remote authenticated users to cause silent filter misparsing through internal strings. The ldap_utf8prev() function reads as many as six bytes before a heap buffer when str2simple parses an internal filter containing an equals sign at or near its start. Normal BER-encoded LDAP search filters do not reach this parser; access to plugin configuration, ACI definitions, or replication-delivered configuration is required, and production builds return incorrect search results rather than crashing.
Summary
What happened
Heap buffer over-read in Red Hat Directory Server allows remote authenticated users to cause silent filter misparsing through internal strings. The ldap_utf8prev() function reads as many as six bytes before a heap buffer when str2simple parses an internal filter containing an equals sign at or near its start. Normal BER-encoded LDAP search filters do not reach this parser; access to plugin configuration, ACI definitions, or replication-delivered configuration is required, and production builds return incorrect search results rather than crashing.
The record
- CVE
- CVE-2026-11787
- Published
- Jun 9, 2026
- Updated
- Jun 9, 2026
- Vendor
- 389 Directory Server
- Product
- Red Hat Directory Server
- Classifications
- CWE-126
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Jun 9, 2026CVE publishedPublication date reported by the CVE source.
- Jun 9, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo