# CVE-2026-8350: Concrete CMS is vulnerable to missing authorization in the bulk_user_assignment.php

> Authenticated users can escalate privileges to Administrative Group by adding or removing users from groups via the bulk user assignment page.

- **Severity:** High 7.5 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 21 May 2026
- **Updated:** 22 May 2026
- **Also known as:** GHSA-g7xp-jf3x-wcx4

## What is CVE-2026-8350?

CVE-2026-8350 is a high-severity missing authorization vulnerability in Concretecms Concrete Cms, published on 21 May 2026. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

Concrete CMS 9.5.0 and below is vulnerable to missing authorization in the bulk_user_assignment.php which can lead to privilege escalation to Administrative Group. Any authenticated user with access to the bulk user assignment dashboard page can add any user email to any group and can remove legitimate admins. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 7.5 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N. Thanks Vincent55 for reporting.

Weakness: CWE-863 (Incorrect Authorization)

## Which versions are affected by CVE-2026-8350?

2 open source packages ship an affected version, including concrete5/concrete5. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `concrete5/concrete5` | Packagist | All versions | 9.5.1 |
| `concrete5/concrete5` | Packagist | All versions | 9.5.1 |

Products: Concretecms Concrete Cms.

## How do I fix CVE-2026-8350?

Upgrade concrete5/concrete5 to 9.5.1 or later.

## Is CVE-2026-8350 being exploited?

There is no known exploitation of CVE-2026-8350 in the wild and no public exploit code.

## Other vulnerabilities in Concretecms Concrete Cms

- [CVE-2023-48648](https://insights.sbomify.com/CVE-2023-48648/): Concrete CMS allows unauthorized access because directories can be created with insecure permissions (critical 9.8)
- [CVE-2022-21829](https://insights.sbomify.com/CVE-2022-21829/): Code injection in concrete CMS (critical 9.8)
- [CVE-2021-22958](https://insights.sbomify.com/CVE-2021-22958/): Server-Side Request Forgery vulnerability in concrete5 (critical 9.8)
- [CVE-2021-40098](https://insights.sbomify.com/CVE-2021-40098/): Path traversal in n/a (critical 9.8)
- [CVE-2026-8134](https://insights.sbomify.com/CVE-2026-8134/): Concrete CMS Vulnerable to Relative Path Traversal (critical 9.4)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-8350 and fix it if it is affected.

What it is: CVE-2026-8350 is a high-severity missing authorization vulnerability in Concretecms Concrete Cms, published on 21 May 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-8350 in the wild and no public exploit code.

Affected packages and fixed versions:
- concrete5/concrete5 (Packagist): affected all versions; fixed in 9.5.1
- concrete5/concrete5 (Packagist): affected all versions; fixed in 9.5.1

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-2026-8350/ (Markdown: https://insights.sbomify.com/CVE-2026-8350/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-8350
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-8350
- OSV: https://osv.dev/vulnerability/CVE-2026-8350

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-8350/
Summaries are generated and may contain mistakes; the official description above is the record.