# CVE-2026-81923: Concrete CMS below 9.5.3 is missing authorization in the SEO Bulk Update Meta Tags editor

> Attackers with bulk SEO tool access can modify meta tags and URLs of pages they cannot edit, bypassing per-page edit permissions.

- **Severity:** Low 2.1 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:N/VI:L/VA:N/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:** No
- **Published:** 15 Sep 2026
- **Updated:** 15 Sep 2026
- **Also known as:** GHSA-4q84-hvmx-qpr3

## What is CVE-2026-81923?

CVE-2026-81923 is a low-severity missing authorization vulnerability in Concretecms Concrete Cms, published on 15 Sep 2026. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

In Concrete CMS before 9.5.3, the SEO Bulk Update Meta Tags editor did not check per-page edit permissions before saving. The saveRecord() action validated the per-page CSRF token but never called canEditPageProperties() for the target page, so a user who was granted access to the bulk SEO tool and could view (but not edit) a given page was able to change that page's meta title, meta description, and URL handle outside their edit scope, tampering with the presentation and live URLs of otherwise protected content. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 2.1 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N. Thanks Andrew Gonzalez for reporting.

Weakness: CWE-862 (Missing Authorization)

## Which versions are affected by CVE-2026-81923?

It affects 1 product.


Products: Concretecms Concrete Cms.

## How do I fix CVE-2026-81923?

No fix has been published for CVE-2026-81923 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-81923 being exploited?

There is no known exploitation of CVE-2026-81923 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-2026-81923 and fix it if it is affected.

What it is: CVE-2026-81923 is a low-severity missing authorization vulnerability in Concretecms Concrete Cms, published on 15 Sep 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-81923 in the wild and no public exploit code.

Affected product: Concretecms Concrete Cms. 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-2026-81923/ (Markdown: https://insights.sbomify.com/CVE-2026-81923/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-81923
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-81923
- OSV: https://osv.dev/vulnerability/CVE-2026-81923

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-81923/
Summaries are generated and may contain mistakes; the official description above is the record.