Exploited vulnerability · CISA KEV
Yes. CVE-2026-81578, PaperCut NG/MF Missing Authentication for Critical Function Vulnerability, is being exploited in the wild. CISA added it to its Known Exploited Vulnerabilities catalog on 31 Aug 2026, 3 days after it was published. It affects PaperCut NG/MF. If you run it, CISA's required action is: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
PaperCut NG/MF contains a missing authentication for critical function vulnerability which allows an unauthenticated remote attacker to modify certain system configurations. This vulnerability can be chained with CVE-2026-82078.
| Vendor | PaperCut (5 exploited CVEs in KEV) |
| Product | NG/MF |
| Vulnerability | PaperCut NG/MF Missing Authentication for Critical Function Vulnerability |
| Weakness | CWE-306 |
| Published | 28 Aug 2026 |
| Added to KEV | 31 Aug 2026 |
| Reported by (CNA) | PaperCut |
Yes. CISA added CVE-2026-81578 to the Known Exploited Vulnerabilities catalog on 31 Aug 2026, which means there is reliable evidence of exploitation in the wild.
CISA does not list known ransomware use for it. That can change, and exploitation alone is reason to fix it first.
Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines. Check PaperCut's advisory for the fixed versions, and if you can't patch quickly, restrict access to the affected NG/MF and watch it for signs of compromise.
Sources: CISA KEV (exploitation, ransomware use, required action, due date), the CVE record (publication date, CVSS, CNA), NVD and FIRST EPSS (live score). More: all KEV additions in August 2026 · PaperCut scorecard · act-now radar.
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