Medium [CVE-2026-12528] 389-ds-base: 389-ds-base: heap-buffer-overflows in __aclp__normalize_acltxt
This medium-severity Red Hat Linux advisory covers CVE-2026-12528 affecting Red Hat Directory Server 11, Red Hat Directory Server 12, Red Hat Directory Server 13.
Aggregated and source-linked by VulniPulse. Data sources, validation and limitations.
VulniPulse record published
Summary
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.
This flaw in 389 Directory Server has a Low impact. While modern Red Hat Directory Server configurations typically limit write access to the `aci` attribute to the Directory Manager, certain older deployments or custom ACI patterns could allow other authenticated users to introduce the malformed string.
The resulting 1-byte heap corruption is silent in production builds and is not considered weaponizable for code execution. Red Hat severity: Low — CVSS 5.4 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L).
Weakness: CWE-787. Affected Red Hat products: Red Hat Directory Server 11; Red Hat Directory Server 12; Red Hat Directory Server 13; Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 6; Red Hat Enterprise Linux 7; Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9.
Is CVE-2026-12528 exploited?
No exploitation is reported in the sources VulniPulse tracks: CVE-2026-12528 is not in the CISA KEV catalog (checked ) and this advisory does not report exploitation. That is not proof the vulnerability cannot be exploited.
How do I fix CVE-2026-12528?
The advisory VulniPulse tracks names no fixed release. Follow Red Hat's guidance for workarounds and updates.
Confirm against the vendor advisory before you patch.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative. Check it before change work.
Official advisory · high-confidence parse· fetched 3 days ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists. Confirm against the vendor advisory.
Official advisory · high-confidence parse· fetched 3 days ago·verify at source
Mitigation checklist
- Ensure that only highly privileged accounts (Directory Manager or explicitly delegated ACI administrators) have write access to the 'aci' attribute. Review existing ACIs for overly broad targetattr rules (especially negated rules like targetattr!="..." or wildcards like targetattr="*") that may inadvertently grant regular users write access to operational attributes including 'aci'. The 389 DS ACI linting tool (lib389) can help identify such misconfigurations.
Official advisory · high-confidence parse· fetched 3 days ago·verify at source
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