BentoPDF’s deserializeWorkflow() accepts a JSON workflow that contains a Timestamp node with a user-controlled tsaUrl. The timestampPdf() routine sends an RFC 3161 TimeStampReq to the specified endpoint, which includes the PDF’s SHA‑256 MessageImprint. Because the application does not validate this URL, an attacker can cause the client to transmit the PDF hash to an arbitrary server. The disclosed hash reveals that a user’s document matches a known file and enables cross‑user correlation, but it does not expose the document contents.

Versions of BentoPDF 2.8.6 and earlier issued by alam00000 are affected. The vulnerability is fixed in release 2.8.7.

The CVSS score of 3.4 indicates low severity. EPSS is not available and the vulnerability is not listed in the CISA KEV catalog. The likely attack vector is a user importing a malicious workflow file; the attacker chooses the tsaUrl, causing the client to send a timestamp request directly to the chosen endpoint. The attack does not require elevated privileges or code execution and relies on client trust of imported JSON. If exploitation occurs, it results only in hash exfiltration and document correlation.