CVE-2026-12528
CWE-787Published: June 17, 2026· Updated: Jun 17, 2026
Official Description
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.
Technical Analysis
CVE-2026-12528 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.
Exploitation requires low privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
From a weakness classification perspective (CWE-787): Out-of-bounds write vulnerabilities can lead to data corruption, crashes, or arbitrary code execution.
CVSS v3.1 Vector Breakdown
Exploit & PoC Resources
All References (3)
Quick Facts
Related CVEs (CWE-787)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2026-12528 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts