A flaw was found in 389 Directory Server. During schema reload, the attr_syntax_swap_ht() function unconditionally frees attribute syntax information nodes, bypassing the refcount-based deferred deletion used elsewhere in the attribute syntax subsystem. If an administrator triggers schema reload while concurrent LDAP query traffic is active, worker threads may access freed memory, resulting in use-after-free or double-free and a denial of service (server crash).

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Fixes

Solution

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Workaround

Schedule schema reload operations during maintenance windows with reduced LDAP traffic. Minimize schema reload frequency; in replication topologies schema changes propagate automatically. Monitor for unexpected ns-slapd restarts during or immediately after schema reloads. Restrict write access to cn=schema,cn=config to dedicated administrative accounts via LDAP ACIs.

History

Thu, 18 Jun 2026 17:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Thu, 18 Jun 2026 16:45:00 +0000

Type Values Removed Values Added
Description A flaw was found in 389 Directory Server. During schema reload, the attr_syntax_swap_ht() function unconditionally frees attribute syntax information nodes, bypassing the refcount-based deferred deletion used elsewhere in the attribute syntax subsystem. If an administrator triggers schema reload while concurrent LDAP query traffic is active, worker threads may access freed memory, resulting in use-after-free or double-free and a denial of service (server crash).
Title 389-ds-base: 389-ds-base: use-after-free in schema reload via attr_syntax_swap_ht()
First Time appeared Redhat
Redhat directory Server
Redhat enterprise Linux
Weaknesses CWE-416
CPEs cpe:/a:redhat:directory_server:11
cpe:/a:redhat:directory_server:12
cpe:/a:redhat:directory_server:13
cpe:/o:redhat:enterprise_linux:10
cpe:/o:redhat:enterprise_linux:6
cpe:/o:redhat:enterprise_linux:7
cpe:/o:redhat:enterprise_linux:8
cpe:/o:redhat:enterprise_linux:9
Vendors & Products Redhat
Redhat directory Server
Redhat enterprise Linux
References
Metrics cvssV3_1

{'score': 5, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:L/A:H'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: redhat

Published:

Updated: 2026-06-18T15:24:19.371Z

Reserved: 2026-06-09T13:01:16.818Z

Link: CVE-2026-11791

cve-icon Vulnrichment

Updated: 2026-06-18T15:24:15.461Z

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses