PaperCut NG/MF Missing Authentication for Critical Function Vulnerability. Actively exploited: CISA added this vulnerability to its Known Exploited Vulnerabilities catalog on 31/08/2026. Patch affected systems as an emergency.
| Package | Affected versions | Patched versions |
|---|---|---|
| papercut mf | ≥ 25.0.2, < 25.0.12≥ 26.0.2, < 26.0.4< 24.1.9 | 25.0.1226.0.424.1.9 |
| papercut ng | ≥ 25.0.2, < 25.0.12≥ 26.0.2, < 26.0.4< 24.1.9 | 25.0.1226.0.424.1.9 |
An improper access control vulnerability exists in the web management interface of PaperCut MF and PaperCut NG. Under specific conditions, unauthenticated remote requests targeting administrative functions can trigger backend actions prior to the completion of access validation checks. This allows an unauthenticated remote attacker to modify certain system configurations.
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