389 DS Use-After-Free via Unref'd Attr_Syntax Swap during Schema Reload
CVE-2026-11791 Published on June 18, 2026
389-ds-base: 389-ds-base: use-after-free in schema reload via attr_syntax_swap_ht()
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).
Vulnerability Analysis
CVE-2026-11791 can be exploited with network access, and requires user privileges. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality, with no impact on integrity, and a high impact on availability.
Timeline
Reported to Red Hat.
Made public.
Weakness Type
What is a Dangling pointer Vulnerability?
Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code.
CVE-2026-11791 has been classified to as a Dangling pointer vulnerability or weakness.
Products Associated with CVE-2026-11791
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