# CVE-2026-81898: Cross-site scripting in Concrete CMS

> Attackers can inject malicious scripts via Address attributes in Concrete CMS, potentially hijacking dashboard user sessions.

- **Severity:** High 7.5 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 15 Sep 2026
- **Updated:** 20 Sep 2026
- **Also known as:** GHSA-fvp6-f7j9-p236

## What is CVE-2026-81898?

CVE-2026-81898 is a high-severity cross-site scripting vulnerability in Concrete CMS, published on 15 Sep 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### Official description

In Concrete CMS below version 9.5.3, the Address attribute's country-less text formatter skipped HTML-escaping, enabling stored XSS in Express association views. A user able to submit an Address attribute could execute script in the session of any dashboard user who opened the affected entry. The unescaped branch was reachable because a non-required Address attribute accepted a blank country, and because several Express association templates (for example concrete/elements/express/form/view/dashboard/association.php) echoed the association label mask without applying h(). The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 7.5 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N. Thanks Yonatan Drori from Tenzai for reporting.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2026-81898?


## How do I fix CVE-2026-81898?

No fix has been published for CVE-2026-81898 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-81898 being exploited?

There is no known exploitation of CVE-2026-81898 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-81898 and fix it if it is affected.

What it is: CVE-2026-81898 is a high-severity cross-site scripting vulnerability in Concrete CMS, published on 15 Sep 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-81898 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-2026-81898/ (Markdown: https://insights.sbomify.com/CVE-2026-81898/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-81898
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-81898
- OSV: https://osv.dev/vulnerability/CVE-2026-81898

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-81898/
Summaries are generated and may contain mistakes; the official description above is the record.