CVE-2026-12528: Red Hat 389 Directory Server

Medium severity, CVSS 5.4. EPSS: 0.2% chance of exploitation in the next 30 days.

A flaw was found in 389 Directory Server in the __aclp__normalize_acltxt() function of aclparse.c. A malformed ACI (Access Control Instruction) string can trigger heap-buffer-overflow writes and reads during ACI parsing. The function fails to validate that the ACI keyword has sufficient length after whitespace stripping, leading to a 1-byte out-of-bounds write and subsequent out-of-bounds reads. An authenticated user with write access to the aci attribute could send a crafted ACI value to silently corrupt heap memory in the directory server process.

Affected products

• Red Hat 389 Directory Server: affected versions not specified
• Red Hat Directory Server: version 11.0 only; version 12.0 only; version 13.0 only
• Red Hat Enterprise Linux: version 7.0 only; version 8.0 only; version 9.0 only; version 10.0 only

Published 2026-06-17. Last modified 2026-06-28.