PaperCut NG/MF vulnerability

PaperCut NG/MF contains an observable timing discrepancy in its authentication component. An unauthenticated remote attacker can exploit this vulnerability to perform username enumeration by measuring response times during login attempts. The system executes a password hash comparison only when a valid account is supplied, creating a measurable timing oracle that reveals account existence.

Published 3 Aug 2026Updated 9 Sep 20261 sources
CVSS 6.9

What happened

PaperCut NG/MF contains an observable timing discrepancy in its authentication component. An unauthenticated remote attacker can exploit this vulnerability to perform username enumeration by measuring response times during login attempts. The system executes a password hash comparison only when a valid account is supplied, creating a measurable timing oracle that reveals account existence.

Affected versions

PaperCut NG/MF: before 26.0.3 (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.