OpenSign vulnerability

OpenSign through 2.41.3 fails to validate caller identity in the getDocument cloud function when one-time-password verification is disabled. Attackers can supply a document identifier from guest signing links to retrieve complete document details including all signers' information, sender identity, and valid download tokens without authentication.

Published 16 Sep 2026Updated 22 Sep 20264 sources
CVSS 8.7

What happened

OpenSign through 2.41.3 fails to validate caller identity in the getDocument cloud function when one-time-password verification is disabled. Attackers can supply a document identifier from guest signing links to retrieve complete document details including all signers' information, sender identity, and valid download tokens without authentication.

Affected versions

OpenSign: 0 through 2.41.3 (semver) Fixed: See vendor advisory.

Why it matters

Review the vendor advisory and exposure of the affected product to determine operational impact.

Detection & mitigation

  • Apply vendor-provided updates or mitigations.
  • Review affected product exposure and access logs.

Public PoC references

No public PoC reference has passed the current publication threshold.