Improper Sanitization of SVG Files Allows Arbitrary JavaScript Execution in Discourse

CVE-2023-30538 · MEDIUM Severity

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Discourse is an open source platform for community discussion. Due to the improper sanitization of SVG files, an attacker can execute arbitrary JavaScript on the users’ browsers by uploading a crafted SVG file. This issue is patched in the latest stable and tests-passed versions of Discourse. Users are advised to upgrade. For users unable to upgrade there are two possible workarounds: enable CDN handing of uploads (and ensure the CDN sanitizes SVG files) or disable SVG file uploads by ensuring that the `authorized extensions` site setting does not include `svg` (or reset that setting to the default, by default Discourse doesn't enable SVG uploads by users).

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