# CVE-2026-18651: Auth bypass in Red Hat Directory Server 11

> Attackers with valid credentials for locked accounts can bypass account lockout controls and maintain access due to improper state handling during SASL PLAIN authentication.

- **Severity:** Medium 5.4 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 3 Aug 2026
- **Updated:** 3 Aug 2026
- **Also known as:** AZL-94517, DEBIAN-CVE-2026-18651, GHSA-q924-9ph6-5h92, UBUNTU-CVE-2026-18651

## What is CVE-2026-18651?

CVE-2026-18651 is a medium-severity authentication bypass vulnerability in Redhat Enterprise Linux, published on 3 Aug 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. During SASL PLAIN authentication, the server installs connection-level bind credentials before performing the account-lock check. If the account is subsequently found to be locked, the bind is reported as failed to the client, but the already-installed authenticated state on the connection is not reverted. A client that supplies valid credentials for an account that has been administratively locked can continue to use the same connection with that account's privileges, defeating account lock as an access-revocation control.

Weakness: CWE-287 (Improper Authentication)

## Which versions are affected by CVE-2026-18651?

It affects 3 products.


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

## How do I fix CVE-2026-18651?

No fix has been published for CVE-2026-18651 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-18651 being exploited?

There is no known exploitation of CVE-2026-18651 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-2026-18651 and fix it if it is affected.

What it is: CVE-2026-18651 is a medium-severity authentication bypass vulnerability in Redhat Enterprise Linux, published on 3 Aug 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-2026-18651 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-2026-18651/ (Markdown: https://insights.sbomify.com/CVE-2026-18651/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-18651
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-18651
- OSV: https://osv.dev/vulnerability/CVE-2026-18651

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-18651/
Summaries are generated and may contain mistakes; the official description above is the record.