CVE-2026-12528 389-ds-base: 389-ds-base: heap-buffer-overflows in aclpnormalize_acltxt()

Medium 5.4 Published 17 Jun 2026 Updated 17 Jun 2026

An authenticated user can trigger heap buffer overflows in 389 Directory Server via crafted ACI strings, potentially leading to code execution or crashes.

Exploited in the wild: Not known
Login needed: Any signed-in user
Attackable: Over the internet
Victim action needed: Not needed
Fix: Available

What is CVE-2026-12528?

CVE-2026-12528 is a medium-severity memory corruption vulnerability in Redhat Enterprise Linux, published on 17 Jun 2026. Any signed-in user can exploit it over the network, with no action from the victim.

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.

Weakness: CWE-787

Which versions are affected by CVE-2026-12528?

It affects 3 products.

Products include Redhat 389 Directory Server, Redhat Directory Server, Redhat Enterprise Linux.

How do I fix CVE-2026-12528?

Apply the vendor's patch.

Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.

Is CVE-2026-12528 being exploited?

There is no known exploitation of CVE-2026-12528 in the wild and no public exploit code.

All Redhat Enterprise Linux vulnerabilities

Sources

Also known as DEBIAN-CVE-2026-12528, GHSA-jf4x-778m-8cj9, UBUNTU-CVE-2026-12528.

CVE-2026-12528 389-ds-base: 389-ds-base: heap-buffer-overflows in __aclp__normalize_acltxt()