# CVE-2026-68526: Concrete CMS before 9.5.3 is vulnerable to CSRF in the Calendar event duplicate dialog controller

> Attackers can trick authenticated users into duplicating calendar events via CSRF, modifying data without consent.

- **Severity:** Medium 5.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 11 Sep 2026
- **Updated:** 14 Sep 2026
- **Also known as:** GHSA-7vqm-7j76-2jjr

## What is CVE-2026-68526?

CVE-2026-68526 is a medium-severity vulnerability in Concretecms Concrete Cms, published on 11 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

Concrete CMS before 9.5.3 did not validate an anti-CSRF token in the Calendar event duplicate dialog controller (concrete/controllers/dialog/event/duplicate.php) submit() action, which duplicated a calendar event after checking only canAccess() and the per-resource canAddCalendarEvent() permission, so a crafted cross-site request could cause an authenticated user with add-event permission to create duplicate CalendarEvents and CalendarEventVersions records under their own authority. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 5.3 with vector CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N. Thanks Winston Crooker for reporting.

Weakness: CWE-352 (Cross-Site Request Forgery)

## Which versions are affected by CVE-2026-68526?

It affects 1 product.


Products: Concretecms Concrete Cms.

## How do I fix CVE-2026-68526?

No fix has been published for CVE-2026-68526 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-68526 being exploited?

There is no known exploitation of CVE-2026-68526 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-2026-68526 and fix it if it is affected.

What it is: CVE-2026-68526 is a medium-severity vulnerability in Concretecms Concrete Cms, published on 11 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-68526 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-2026-68526/ (Markdown: https://insights.sbomify.com/CVE-2026-68526/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-68526
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-68526
- OSV: https://osv.dev/vulnerability/CVE-2026-68526

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-68526/
Summaries are generated and may contain mistakes; the official description above is the record.