# CVE-2026-9811: Mautic has Stored Cross-Site Scripting (XSS) in Project Option Selector

> Authenticated users can inject scripts via project names, leading to session hijacking and data access for administrators.

- **Severity:** Medium 5.4 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A: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:** Yes
- **Published:** 29 May 2026
- **Updated:** 29 May 2026
- **Also known as:** GHSA-5hvg-w58j-545m

## What is CVE-2026-9811?

CVE-2026-9811 is a medium-severity cross-site scripting vulnerability in mautic/core, published on 29 May 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

A stored Cross-Site Scripting (XSS) vulnerability exists in the project selector component of Mautic 7. When rendering selection menus for associating projects with system entities, the application fails to sanitize project names returned via AJAX before injecting them into the DOM as option fields. An authenticated user with permissions to create projects can exploit this to store a malicious script payload in the project's name. When another administrative user subsequently opens an entity editor containing the project selector, the injected script executes within the context of their active browser session. This could allow an attacker to hijack the session, perform unauthorized state coordination, or access organizational data within the dashboard.

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

## Which versions are affected by CVE-2026-9811?

2 open source packages ship an affected version, including mautic/core.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `mautic/core` | Packagist | From 7.0.0 | 7.1.2 |
| `mautic/core` | Packagist | From 7.0.0 | 7.1.2 |

## How do I fix CVE-2026-9811?

Upgrade mautic/core to 7.1.2 or later.

## Is CVE-2026-9811 being exploited?

There is no known exploitation of CVE-2026-9811 in the wild and no public exploit code.

Public exploit code:

- CVE-2026-9811 is a Stored Cross-Site Scripting (Stored XSS) vulnerability affecting Mautic 7 (versions 7.0.0 through 7.1.1). (github_poc): https://github.com/aj2108/CVE-2026-9811

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-9811 and fix it if it is affected.

What it is: CVE-2026-9811 is a medium-severity cross-site scripting vulnerability in mautic/core, published on 29 May 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-2026-9811 in the wild and no public exploit code.

Affected packages and fixed versions:
- mautic/core (Packagist): affected from 7.0.0; fixed in 7.1.2
- mautic/core (Packagist): affected from 7.0.0; fixed in 7.1.2

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-2026-9811/ (Markdown: https://insights.sbomify.com/CVE-2026-9811/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-9811
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-9811
- OSV: https://osv.dev/vulnerability/CVE-2026-9811

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-9811/
Summaries are generated and may contain mistakes; the official description above is the record.