CVE-2026-81578
Actively exploited. CVE-2026-81578 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2026-08-31) — exploitation has been observed in the wild, and US federal agencies are required to remediate it under BOD 22-01. Treat patching as urgent.
Public exploit code is available. Proof-of-concept or working exploit code for CVE-2026-81578 is indexed in GitHub PoC. Expect opportunistic scanning and exploitation attempts — prioritize remediation.
CISA has added two new vulnerabilities to its Known Exploited Vulnerabilities (KEV) Catalog , based on evidence of active exploitation. CVE-2026-81578 PaperCut NG/MF Missing Authentication for Critical Function Vulnerability CVE-2026-82078 PaperCut NG/MF Unsafe Reflection Vulnerability These types of vulnerabilities are a frequent attack vector for malicious cyber actors and pose significant risks to the federal enterprise. Binding Operational Directive (BOD) 26-04: Prioritizing Security Updates Based on Risk establishes vulnerability management requirements for Federal Civilian Executive Branch (FCEB) agencies. BOD 26-04 reinforces the importance of the KEV Catalog and requires federal agencies to prioritize rapid remediation of high-risk vulnerabilities, specifically those identified by Common Vulnerabilities and Exposures (CVEs) listed in CISA’s KEV Catalog on publicly exposed assets that grant total control of the asset post-exploitation, while deferring action for lower-risk vulnerabilities. BOD 26-04 further establishes basic expectations for when agencies must check whether threat actors compromised the system before the patch was applied. While BOD 26-04 applies only to FCEB agencies, CISA encourages all organizations to adopt risk-based vulnerability management and prioritize remediation of KEV Catalog vulnerabilities . CISA will continue to add vulnerabilities to the catalog that meet the specified criteria . Aware of an exploited vulnerability not currently listed in the KEV Catalog? Submit it for potential addition through CISA’s KEV Nomination Form . Potential KEV additions must have a CVE ID, evidence of exploitation, and clear mitigation guidance.
CSIRTS triage
- What
- Papercut contains authentication bypass and remote code execution vulnerabilities.
- Who is affected
- All Papercut installations are affected; vulnerabilities are being actively exploited in the wild.
- Urgency
- Critical; active exploitation confirmed for authentication bypass and RCE vulnerabilities.
- Action
- Apply Papercut security patches immediately or implement request filtering as indicated by the publisher.
AI-assisted analysis generated from the source advisory — verify against the original.
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Exploitation outlook
- Exploitation confirmedAlready exploited in the wild (CISA KEV) — the prediction phase is over. Patch now. Riskier than 53% of all EPSS-scored CVEs.
Exploit availability
Public exploit or proof-of-concept code for CVE-2026-81578 is indexed in these free datasets. Available exploit code raises real-world risk independent of the CVSS score.
- GitHub PoCPublic proof-of-concept repositories on GitHub reference this CVE.look it up ↗
Advisory coverage (7)
- unknownexploitedPaperCut security advisory (AV26-858) – Update 2cccs · 2026-08-31
- criticalexploitedCISA Adds Two Known Exploited Vulnerabilities to Catalogcisa · 2026-08-31
- unknownexploitedPaperCut Multiple Vulnerabilitieshkcert · 2026-08-31
- criticalexploitedCVE-2026-81578: PaperCut NG/MF Missing Authentication for Critical Function Vulnerabilitycisa-kev · 2026-08-31
- criticalexploitedCVE-2026-81578: An improper access control vulnerability exists in the web management interface of PaperCut MF…nvd · 2026-08-28
- unknownexploitedNCSC-2026-0334 [1.00] [M/H] Vulnerabilities patched in PaperCut MF and PaperCut NG from PaperCutncsc-nl · 2026-08-28
- unknownexploitedMultiple vulnerabilities in Papercut (August 28, 2026)cert-fr-avis · 2026-08-28
External references
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