Use After Free in Red Hat Directory Server 11
CVE-2026-11791
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 class: Use-After-Free
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.0 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:L/A:H.
EPSS exploit prediction
EPSS: 0.004 (26.1th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 26th percentile — 26.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.004 · change: +0.001
Affected products
Weakness classification (CWE)
References
- access.redhat.com/security/cve/CVE-2026-11791 (Mitigation, vdb-entry, Vendor Advisory)
- bugzilla.redhat.com/show_bug.cgi (issue-tracking, Issue Tracking, Vendor Advisory)
- redhat.atlassian.net/browse/PSIRTSUPT-7600 (Permissions Required)
Frequently asked questions
- What is CVE-2026-11791?
- CVE-2026-11791 is a medium-severity vulnerability in Red Hat Directory Server 11, classified under Use After Free. CVSS score: 5.0/10. Published 2026-06-18.
- How severe is CVE-2026-11791?
- Medium severity. CVSS v3 base score is 5.0 out of 10.