CVE-2026-75529 Stored Cross-Site Scripting via MIME-Type Confusion in PDF Downloads of Pandora
Attackers can execute arbitrary scripts in victims' browsers via stored XSS in Pandora's PDF download feature, potentially accessing sensitive application data.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-75529?
CVE-2026-75529 is a medium-severity cross-site scripting vulnerability in pandora-analysis pandora, published on 17 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Pandora is affected by a stored cross-site scripting vulnerability in the PDF download functionality. The /task-download/<task_id>/.../pdf endpoint verifies that the submitted file is a PDF using Pandora's content-based file-type detection, but previously returned the file using send_file(task.file.path) without explicitly specifying the MIME type or forcing it to be downloaded as an attachment.
Because Flask determines the response MIME type from the filename when a path is supplied, an attacker could submit a file whose content is recognized by Pandora as a PDF while its filename or extension causes the download endpoint to return it with a different, potentially active MIME type.
A specially crafted PDF/polyglot file could therefore be served inline and interpreted by a victim's browser as HTML or another executable web format. If a victim with access to the submitted analysis follows the PDF download link, attacker-controlled script could execute in the security context of the Pandora application, potentially allowing access to application data or actions using the victim's session.
The patch prevents the issue by explicitly returning PDF downloads with Content-Type: application/pdf, forcing Content-Disposition: attachment, and assigning a trusted .pdf filename based on the task UUID.
Weakness: CWE-79
Which versions are affected by CVE-2026-75529?
How do I fix CVE-2026-75529?
No fix has been published for CVE-2026-75529 yet. Limit exposure of the affected software until one is available.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-75529 being exploited?
There is no known exploitation of CVE-2026-75529 in the wild and no public exploit code.