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

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

- **Severity:** Medium 5.4 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 17 Jun 2026
- **Updated:** 17 Jun 2026
- **Also known as:** DEBIAN-CVE-2026-12528, GHSA-jf4x-778m-8cj9, UBUNTU-CVE-2026-12528

## 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 (Out-of-bounds Write)

## Which versions are affected by CVE-2026-12528?

It affects 3 products.


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

## How do I fix CVE-2026-12528?

Apply the vendor's patch.

## Is CVE-2026-12528 being exploited?

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

## Other vulnerabilities in Redhat Enterprise Linux

- [CVE-2026-11770](https://insights.sbomify.com/CVE-2026-11770/): 389-ds-base: 389-ds-base: pre-auth ldap filter injection in cleanallruv status check (high 7.5)
- [CVE-2026-15722](https://insights.sbomify.com/CVE-2026-15722/): Memory corruption in Red Hat Directory Server 11.5 E4S for RHEL 8 (high 7.5)
- [CVE-2026-9064](https://insights.sbomify.com/CVE-2026-9064/): Denial of service in Red Hat Directory Server 11.5 E4S for RHEL 8 (high 7.5)
- [CVE-2010-2222](https://insights.sbomify.com/CVE-2010-2222/): Null dereference in Red Hat Directory Server (high 7.5)
- [CVE-2026-11611](https://insights.sbomify.com/CVE-2026-11611/): 389-ds-base: 389-ds-base: content sync plugin unbounded queue growth and race conditions (medium 6.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-12528 and fix it if it is affected.

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

Affected product: Redhat Enterprise Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-12528/ (Markdown: https://insights.sbomify.com/CVE-2026-12528/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-12528
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-12528
- OSV: https://osv.dev/vulnerability/CVE-2026-12528

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-12528/
Summaries are generated and may contain mistakes; the official description above is the record.