# CVE-2026-104038: Sssd: sssd: denial of service via missing sid extension in certificate mapping

> Remote attackers can crash the SSSD service by submitting certificates missing SID extensions in specific configurations, causing denial of service.

- **Severity:** Medium 5.9 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 6 Oct 2026
- **Updated:** 16 Oct 2026
- **Also known as:** DEBIAN-CVE-2026-104038, GHSA-qr5w-232p-j88j, UBUNTU-CVE-2026-104038

## What is CVE-2026-104038?

CVE-2026-104038 is a medium-severity vulnerability in Red Hat Enterprise Linux 10, published on 6 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A flaw was found in sssd. A remote attacker can cause a denial of service (DoS) by submitting a certificate that lacks an expected Security Identifier (SID) extension. In deployments configured with SID-based certificate mapping rules, the service fails to verify the presence of the extension before processing it, causing the process to crash during authentication or lookup operations.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2026-104038?


## How do I fix CVE-2026-104038?

Apply the vendor's patch.

## Is CVE-2026-104038 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-104038 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-104038 and fix it if it is affected.

What it is: CVE-2026-104038 is a medium-severity vulnerability in Red Hat Enterprise Linux 10, published on 6 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-104038 exists.

Affected product: Red Hat Enterprise Linux 10. 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-2026-104038/ (Markdown: https://insights.sbomify.com/CVE-2026-104038/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-104038
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-104038
- OSV: https://osv.dev/vulnerability/CVE-2026-104038

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-104038/
Summaries are generated and may contain mistakes; the official description above is the record.