CVE-2026-18663
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Summary
A flaw was found in 389-ds-base. The get_ldapmessage_controls_ext() function frees the parsed controls array on the Session Tracking critical-control rejection path without clearing the SLAPI_REQCONTROLS pblock slot. Operation teardown then frees the same pointer again, causing a double-free. An unauthenticated remote attacker can trigger this with a single BIND request carrying a critical Session Tracking control, resulting in heap corruption and potential denial of service.
Affected Software
| Vendor | Product | Version Range | Status |
|---|
Weaknesses
- CWE-415: Double Free
Workarounds
On builds that include upstream Issue 7389 (committed 2026-04-09, present in 389-ds-base-3.2 branch), administrators can add the Session Tracking control OID (1.3.6.1.4.1.21008.108.63.1) to the ds-ignored-control-criticality configuration attribute. This causes the server to ignore the criticality flag on this control, preventing the vulnerable rejection path from being reached.
Additionally, network-level restriction of access to the LDAP port (389/636) to trusted clients reduces exposure.
References
- https://access.redhat.com/security/cve/CVE-2026-18663
- https://bugzilla.redhat.com/show_bug.cgi?id=2510631
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