CVE-2026-81578: PaperCut NG/MF Missing Authentication for Critical Function Vulnerability
Actively exploited. At least one CVE in this advisory is listed in the CISA Known Exploited Vulnerabilities catalog — exploitation has been observed in the wild. Treat remediation as urgent.
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.
CSIRTS triage
- What
- Missing authentication for critical function allows unauthenticated remote attackers to modify system configurations.
- Who is affected
- All deployments of PaperCut NG/MF are affected.
- Urgency
- Critical; actively exploited and chainable with CVE-2026-82078 for remote code execution.
AI-assisted analysis generated from the source advisory — verify against the original.
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Details
Original advisory: https://nvd.nist.gov/vuln/detail/CVE-2026-81578
Exploitation outlook
EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.
- Exploitation confirmedCVE-2026-81578Already exploited in the wild (CISA KEV) — the prediction phase is over. Patch now. Riskier than 53% of all EPSS-scored CVEs.
Referenced CVEs
| CVE | CSIRTS overview | External |
|---|---|---|
| CVE-2026-81578 | coverage & exploitation status | NVD · CVE.org |
Same CVEs, other sources
How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.
- unknownexploitedPaperCut security advisory (AV26-858) – Update 2cccs
- criticalexploitedCISA Adds Two Known Exploited Vulnerabilities to Catalogcisa
- unknownexploitedPaperCut Multiple Vulnerabilitieshkcert
- criticalexploitedCVE-2026-81578: An improper access control vulnerability exists in the web management interface of PaperCut MF…nvd
- unknownexploitedNCSC-2026-0334 [1.00] [M/H] Vulnerabilities patched in PaperCut MF and PaperCut NG from PaperCutncsc-nl
- unknownexploitedMultiple vulnerabilities in Papercut (August 28, 2026)cert-fr-avis
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