Medium [CVE-2026-11787] 389-ds-base: 389-ds-base: heap buffer over-read in ldap_utf8prev via str2simple filter parsing
This medium-severity Red Hat Linux advisory covers CVE-2026-11787 affecting Red Hat Directory Server 11, Red Hat Directory Server 12, Red Hat Directory Server 13.
Aggregated and source-linked by VulniPulse. Data sources, validation and limitations.
VulniPulse record published
Summary
A 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.
Red Hat rates this issue as Moderate impact. In 389-ds-base, internal text-based LDAP filter parsing can read up to six bytes before a heap buffer when a filter string has = at or near the start.
Production builds do not crash; the practical effect is silent filter misparse—search results may be wrong, including where ACIs use targetfilter. This path is not reached by normal LDAP search filters on the wire (BER-encoded filters use a separate parser).
An attacker must influence internal filter strings—for example plugin configuration (originFilter, nsUniqueAttribute), ACI definitions, or replication-delivered config. Red Hat severity: Moderate — CVSS 5 (CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L).
Weakness: CWE-126. Affected Red Hat products: Red Hat Directory Server 11; Red Hat Directory Server 12; Red Hat Directory Server 13; Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 6; Red Hat Enterprise Linux 7; Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9.
Will not fix / out of support: Red Hat Enterprise Linux 6. Red Hat does not currently list a fixing RHSA for this CVE.
Is CVE-2026-11787 exploited?
No exploitation is reported in the sources VulniPulse tracks: CVE-2026-11787 is not in the CISA KEV catalog (checked ) and this advisory does not report exploitation. That is not proof the vulnerability cannot be exploited.
How do I fix CVE-2026-11787?
The advisory VulniPulse tracks names no fixed release. Follow Red Hat's guidance for workarounds and updates.
Confirm against the vendor advisory before you patch.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative. Check it before change work.
Official advisory · high-confidence parse· fetched 4 days ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists. Confirm against the vendor advisory.
Official advisory · high-confidence parse· fetched 4 days ago·verify at source
Mitigation checklist
- No direct workaround addresses the code-level bug; network-level mitigations (proxies, WAFs, filter validation) do not apply. Mitigation measures to reduce exposure: restrict plugin configuration access (MEP originFilter, UID uniqueness nsUniqueAttribute, strict ACIs on cn=config); restrict Directory Manager access for ACI, MEP, or uniqueness plugin configuration; harden replication topology to restrict replication peers; monitor for anomalous search result sets that may indicate exploitation.
Official advisory · high-confidence parse· fetched 4 days ago·verify at source
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