# CVE-2026-68527: Missing authorization in Concrete CMS

> Attackers with limited calendar permissions can read, modify, or delete events on unauthorized calendars due to improper authorization checks in the edit dialog.

- **Severity:** Medium 5.9 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:L/VI:H/VA:L/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:** 10 Sep 2026
- **Updated:** 10 Sep 2026
- **Also known as:** GHSA-xgrc-pc59-m8cp

## What is CVE-2026-68527?

CVE-2026-68527 is a medium-severity missing authorization vulnerability in Concrete CMS, published on 10 Sep 2026. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

Concrete CMS versions 8.3.0 through 9.5.2 are vulnerable to an authorization bypass in the Calendar event edit dialog (concrete/controllers/dialog/event/edit.php). The dialog checked permissions against the calendar identifier supplied in the request rather than the calendar owning the targeted event occurrence. A user with the "Add Event" permission on a single calendar could read and overwrite events on calendars they were not permitted to access, and could delete an event's original local occurrence. Publishing the injected version to the live calendar, which demotes the previously approved version, additionally required the actor's approve_calendar_event workflow rights or an auto-approving workflow. The Concrete CMS Security Team gave this a rank of 5.9 with CVSS 4.0 vector CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:L/VI:H/VA:L/SC:N/SI:N/SA:N. Thanks Winston Crooker for reporting.

Weakness: CWE-639 (Authorization Bypass Through User-Controlled Key)

## Which versions are affected by CVE-2026-68527?


## How do I fix CVE-2026-68527?

No fix has been published for CVE-2026-68527 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-68527 being exploited?

There is no known exploitation of CVE-2026-68527 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-68527 and fix it if it is affected.

What it is: CVE-2026-68527 is a medium-severity missing authorization vulnerability in Concrete CMS, published on 10 Sep 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-68527 in the wild and no public exploit code.

Affected product: 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-2026-68527/ (Markdown: https://insights.sbomify.com/CVE-2026-68527/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-68527
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-68527
- OSV: https://osv.dev/vulnerability/CVE-2026-68527

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-68527/
Summaries are generated and may contain mistakes; the official description above is the record.