389-ds-base: 389-ds-base: use-after-free in schema reload via attr_syntax_swap_ht()

Summary

CVE	CVE-2026-11791
State	PUBLISHED
Assigner	redhat
Source Priority	CVE Program / NVD first with legacy fallback
Published	2026-06-18 16:16:52 UTC
Updated	2026-06-30 11:16:28 UTC
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).

Risk And Classification

Primary CVSS: v3.1 5 MEDIUM from [email protected]

CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:L/A:H

EPSS: 0.002120000 probability, percentile 0.115040000 (date 2026-07-04)

Problem Types: CWE-416 | CWE-416 Use After Free

Version	Source	Type	Score	Severity	Vector
3.1	[email protected]	Primary	5	MEDIUM	`CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:L/A:H`
3.1	[email protected]	Secondary	5	MEDIUM	`CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:L/A:H`
3.1	CNA	CVSS	5	MEDIUM	`CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:L/A:H`

CVSS v3.1 Breakdown

Attack Vector

Network

Attack Complexity

High

Privileges Required

High

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

Low

Availability

High

CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:L/A:H

NVD Known Affected Configurations (CPE 2.3)

Type	Vendor	Product	Version	Update	Edition	Language
Operating System	Redhat	389 Directory Server	-	All	All	All
Application	Redhat	Directory Server	11.0	All	All	All
Application	Redhat	Directory Server	12.0	All	All	All
Application	Redhat	Directory Server	13.0	All	All	All
Operating System	Redhat	Enterprise Linux	10.0	All	All	All
Operating System	Redhat	Enterprise Linux	7.0	All	All	All
Operating System	Redhat	Enterprise Linux	8.0	All	All	All
Operating System	Redhat	Enterprise Linux	9.0	All	All	All

Vendor Declared Affected Products

Source	Vendor	Product	Version	Platforms
CNA	Red Hat	Red Hat Directory Server 11	Not specified	Not specified
CNA	Red Hat	Red Hat Directory Server 12	Not specified	Not specified
CNA	Red Hat	Red Hat Directory Server 13	Not specified	Not specified
CNA	Red Hat	Red Hat Enterprise Linux 10	Not specified	Not specified
CNA	Red Hat	Red Hat Enterprise Linux 6	Not specified	Not specified
CNA	Red Hat	Red Hat Enterprise Linux 7	Not specified	Not specified
CNA	Red Hat	Red Hat Enterprise Linux 8	Not specified	Not specified
CNA	Red Hat	Red Hat Enterprise Linux 9	Not specified	Not specified

References

Reference	Source	Link	Tags
access.redhat.com/security/cve/CVE-2026-11791	[email protected]	access.redhat.com	Mitigation, Vendor Advisory
bugzilla.redhat.com/show_bug.cgi	[email protected]	bugzilla.redhat.com	Issue Tracking, Vendor Advisory
redhat.atlassian.net/browse/PSIRTSUPT-7600	MITRE	redhat.atlassian.net
CVE Program record	CVE.ORG	www.cve.org	canonical
NVD vulnerability detail	NVD	nvd.nist.gov	canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: This issue was discovered by Ian Murphy (Red Hat). (en)

Additional Advisory Data

Source	Time	Event
CNA	2026-04-16T00:00:00.000Z	Reported to Red Hat.
CNA	2026-04-16T00:00:00.000Z	Made public.

Workarounds

CNA: 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.

There are currently no legacy QID mappings associated with this CVE.