{"id":"CVE-2026-18663","title":"389-ds-base: 389-ds-base: pre-authentication double-free in get_ldapmessage_controls_ext() via critical session tracking control","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 t…","severity":"medium","cvss":5.9,"cvssVector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","cvssSource":"cna","cwe":["CWE-415"],"vendor":"Red Hat","product":"redhat-ds:11/389-ds-base","affected":["redhat-ds:11/389-ds-base","redhat-ds:12/389-ds-base","389-ds-base (all versions)","389-ds-base (all versions)","389-ds-base","389-ds-base","389-ds:1.4/389-ds-base","389-ds-base"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-08-13T15:40:56.481579Z"},"published":"2026-08-12","updated":"2026-11-05","sourceUpdated":"2026-11-05T19:25:43.740Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-18663","references":[{"url":"https://access.redhat.com/security/cve/CVE-2026-18663"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2510631","label":"RHBZ#2510631"}],"tags":["cve.org"],"epss":0.00511,"epssPercentile":0.43762,"ingestedAt":"2026-11-05T22:38:31.541Z","slug":"CVE-2026-18663","body":"## Overview\n\nA 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.\n\n## Affected\n\n- `redhat-ds:11/389-ds-base`\n- `redhat-ds:12/389-ds-base`\n- `389-ds-base (all versions)`\n- `389-ds-base (all versions)`\n- `389-ds-base`\n- `389-ds-base`\n- `389-ds:1.4/389-ds-base`\n- `389-ds-base`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n### Workarounds\n\nOn 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.\n\nAdditionally, network-level restriction of access to the LDAP port (389/636) to trusted clients reduces exposure.","depth":"sunlit","depthScore":33,"depthScoreParts":{"impact":32.5,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}