CVE-2026-18663

MEDIUMCVSS 5.9/10

Last modified

CVE-2026-18663 is a medium-severity vulnerability rated 5.9/10 on the CVSS scale. 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.

Description

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.

Metrics

CVSS 3.1
5.9/10

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

Weakness Enumeration

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
Red HatRed Hat Directory Server 13All versions
Red HatRed Hat Enterprise Linux 10All versions

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-18663?
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.
How severe is CVE-2026-18663?
CVE-2026-18663 has a CVSS score of 5.9/10 (MEDIUM severity).
How do I fix CVE-2026-18663?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST