PrivateBin is an online pastebin where the server has zero knowledge of pasted data. Prior to 2.0.5, AttachmentViewer.setAttachment in js/privatebin.js uses getAttachmentMimeType to accept attacker-controlled MIME types and uses getBlobUrl to create a same-origin blob before setting attachmentLink's href for the Download attachment link. The SVG-only sanitization branch updates only the preview blob, so text/html, image/svg, application/xhtml+xml, and text/xml attachments can remain active in the download blob. On an instance with fileupload = true and a weakened, stripped, or absent Content Security Policy, an anonymous attacker can create such an attachment, and a victim who opens the link in a new tab causes inline JavaScript to execute in the PrivateBin origin. The script can read origin-scoped local storage and issue same-origin requests, including requests to applications co-hosted on the same domain. This issue is fixed in version 2.0.5.

Affected: Packagist: privatebin/privatebin

### Summary

Stored cross-site scripting (XSS) in PrivateBin's attachment download link. An anonymous attacker can create a paste with a **text/html** attachment that, with certain user interaction, bypasses protections similar to CVE-2022-24833. When a victim opens the "Download attachment" link in a new tab, the attacker's inline JavaScript executes in the PrivateBin instance's origin with full same-origin capability (cookie/localStorage access, same-origin fetch).

This is an incomplete fix of [CVE-2022-24833](https://github.com/PrivateBin/PrivateBin/security/advisories/GHSA-cqcc-mm6x-vmvw). The original fix only applies to the inline preview blob (in case of SVG), never to the download link's blob. Thus a **text/html** (or **image/svg**) attachment completely bypasses sanitization, re-enabling the exact attack class on instances that don't enforce the recommended Content-Security-Policy, but with a slightly different attack process.

Instances using the default recommended CSP are protected (the blob inherits **script-src 'self'**, blocking inline scripts). The vulnerability affects instances where CSP is weakened, stripped, or absent, which is exactly the defense-in-depth scenario the CVE-2022-24833 fix was meant to cover.

Requires **fileupload = true** (non-default) and a non-recommended CSP configuration.

### Details

In **js/privatebin.js**, the function **AttachmentViewer.setAttachment** (line 2982) processes decrypted attachment data. Since PrivateBin uses zero-k…