Camaleon CMS vulnerable to stored XSS through user file upload (GHSL-2024-184)
Date: 2024-09
Affected: rubygems/camaleon_cms
Attack vector: xss
Category: vulnerability-disclosure
Severity: Medium
CWE: CWE-79
CVSS: 5.4 (CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N)

A stored cross-site scripting has been found in the image upload functionality that can be used by normal registered users: It is possible to upload a SVG image containing JavaScript and it's also possible to upload a HTML document when the format parameter is manually changed to [documents][1] or a string of an [unsupported format][2]. If an authenticated user or administrator visits that uploaded image or document malicious JavaScript can be executed on their behalf (e.g. changing or deleting content inside of the CMS.) [1]: https://github.com/owen2345/camaleon-cms/blob/feccb96e542319ed608acd3a16fa5d92f13ede67/app/uploaders/camaleon_cms_uploader.rb#L105-L106 [2]: https://github.com/owen2345/camaleon-cms/blob/feccb96e542319ed608acd3a16fa5d92f13ede67/app/uploaders/camaleon_cms_uploader.rb#L110-L111 ## Impact This issue may lead to account takeover due to reflected Cross-site scripting (XSS). ## Remediation Only allow the upload of safe files such as PNG, TXT and others or serve all "unsafe" files such as SVG and other files with a content-disposition: attachment header, which should prevent browsers from displaying them. Additionally, a [Content security policy (CSP)][3] can be created that disallows inlined script. (Other parts of the application might need modification to continue functioning.) [3]: https://web.dev/articles/csp To prevent the theft of the auth_token it could be marked with HttpOnly. This would however not prevent that actions could be performed as t


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