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GHSA-v5hf-f4c3-m5rv

MediumCVSS 6.3 / 10

Published Mar 11, 2026·Last modified Mar 13, 2026

Affected Components(0)

No affected components available

Description

Impact

An attacker can upload a file with a file extension or content type that is not blocked by the default configuration of the Parse Server fileUpload.fileExtensions option. The file can contain malicious code, for example JavaScript in an SVG or XHTML file. When the file is accessed via its URL, the browser renders the file and executes the malicious code in the context of the Parse Server domain. This is a stored Cross-Site Scripting (XSS) vulnerability that can be exploited to steal session tokens, redirect users, or perform actions on behalf of other users.

Affected file extensions and content types include .svgz, .xht, .xml, .xsl, .xslt, and content types application/xhtml+xml and application/xslt+xml for extensionless uploads. Uploading of .html, .htm, .shtml, .xhtml, and .svg files was already blocked.

Patches

The fix adds the missing file extensions and content types to the default value of the fileUpload.fileExtensions server option.

Workarounds

Configure the fileUpload.fileExtensions server option to block the affected file extensions and content types.

References

GitHub security advisory: https://github.com/parse-community/parse-server/security/advisories/GHSA-v5hf-f4c3-m5rv
Fix Parse Server 9: https://github.com/parse-community/parse-server/releases/tag/9.6.0-alpha.4
Fix Parse Server 8: https://github.com/parse-community/parse-server/releases/tag/8.6.30

Risk Scores

Base Score

6.3

The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker does not need any special privileges or access rights.

Threat Intelligence

2.3

Limited exploitation activity has been observed. Close monitoring and planned remediation are recommended.

EPSS

0.24%

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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