# CVE-2026-11787: 389-ds-base: 389-ds-base: heap buffer over-read in ldap_utf8prev() via str2simple filter parsing

> A heap buffer over-read in 389 Directory Server allows attackers to potentially crash the service or leak memory contents via crafted string filters.

- **Severity:** Medium 5.0 (`CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/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:** 9 Jun 2026
- **Updated:** 30 Jun 2026
- **Also known as:** DEBIAN-CVE-2026-11787, GHSA-wjcg-9hh3-8323, UBUNTU-CVE-2026-11787

## What is CVE-2026-11787?

CVE-2026-11787 is a medium-severity memory corruption vulnerability in Redhat Enterprise Linux, published on 9 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. The ldap_utf8prev() function reads bytes before the start of a buffer without bounds checking, causing a heap buffer over-read in string filter parsing that may influence internal filter processing behavior.

Weakness: CWE-126 (Buffer Over-read)

## Which versions are affected by CVE-2026-11787?

It affects 3 products.


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

## How do I fix CVE-2026-11787?

Apply the vendor's patch.

## Is CVE-2026-11787 being exploited?

There is no known exploitation of CVE-2026-11787 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-2026-11787 and fix it if it is affected.

What it is: CVE-2026-11787 is a medium-severity memory corruption vulnerability in Redhat Enterprise Linux, published on 9 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-2026-11787 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-2026-11787/ (Markdown: https://insights.sbomify.com/CVE-2026-11787/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-11787
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-11787
- OSV: https://osv.dev/vulnerability/CVE-2026-11787

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-11787/
Summaries are generated and may contain mistakes; the official description above is the record.