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GHSA-pp4x-ccxq-6r33

MediumCVSS 5.4 / 10
Published Sep 2, 2026·Last modified Sep 2, 2026
Affected Components(2)
Packagist logosulu/sulu
< 2.6.25
Packagist logosulu/sulu
3.0.0-alpha1 – 3.0.8
Description

Impact

Stored Cross Site Scripting (XSS) in the media download endpoint.

The download route (/media/{id}/download/{slug} and its admin variant) accepts the query parameter ?inline=1. When it is present, the response is sent with the header Content-Disposition: inline for any MIME type, which overrides the disposition rules the server would otherwise apply. By default, HTML and other scriptable uploads are not blocked, the file is served on the application origin with its stored Content-Type, and no X-Content-Type-Options or Content-Security-Policy header is sent. Because of this, an attacker can upload an HTML file and build a link that runs their own JavaScript in the context of the Sulu origin.

Every installation where users who are not fully trusted can upload media is affected. This includes editors who hold the media add permission. Such an editor can store a payload that runs in the authenticated session of anyone who opens the link, including an administrator, which allows theft of the session and credentials and lets the attacker act as the victim.

The problem is present on the 2.6 and 3.0 branches and goes back to the introduction of the ?inline override in 2017. It is not the same as CVE-2024-47617, which was a reflected XSS through the slug and is already fixed.

Patches

Fixed in 2.6.25 and 3.0.8. The download route now forces Content-Disposition: attachment for MIME types a browser renders as a document (text/html, application/xhtml+xml, text/xml, application/xml), even when ?inline=1 is requested. Inline viewing is unchanged for safe types such as PDF and images.

Workarounds

Block scriptable uploads by MIME type through sulu_media.upload.blocked_file_types. This stops new uploads only, so existing media has to be reviewed separately.

sulu_media:
    upload:
        blocked_file_types: [text/html, application/xhtml+xml, image/svg+xml, text/xml, application/xml, text/javascript, application/javascript]

At the web server or reverse proxy, force Content-Disposition: attachment and add X-Content-Type-Options: nosniff and a restrictive Content-Security-Policy on the paths /media/*/download/* and /admin/media/*/download/*.

Serve uploaded media from a separate origin that does not share the application cookies.

Restrict the media upload permission to trusted users and keep the default SVG sanitizer enabled.

Upload your SBOM

Upload your own SBOM in CycloneDX 1.6 or higher (JSON) directly here to check your vulnerabilities.

Risk Scores
Base Score
5.4

The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker needs basic access or low-level privileges. The attacker needs the user to perform some action, like clicking a link. The vulnerability can affect other systems as well, not just the initial system. There is a low impact on the confidentiality of the information. There is a low impact on the integrity of the data.

Threat Intelligence
5.0

Exploitation attempts have been detected. Elevated vigilance and prompt remediation are advised.

EPSS
0.17%

The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

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