{"id":"CVE-2026-81578","published":"2026-08-28T16:18:29Z","modified":"2026-09-14T00:16:56Z","title":"PaperCut NG/MF Missing Authentication for Critical Function Vulnerability","vendor":"PaperCut","product":"NG/MF","tier":"core","eol":null,"description":{"text":"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.","provenance":"source","from":"NVD"},"summary":{"text":"A flaw in the web management interface of PaperCut MF and PaperCut NG lets backend actions on administrative functions run before access validation completes. An unauthenticated attacker with network access to that interface can, under specific conditions, send remote requests to modify certain system configurations, with no user interaction required.","provenance":"ai","model":"claude-haiku-5-5","generatedAt":"2026-10-29T07:53:21Z"},"cvss":{"score":9.8,"severity":"CRITICAL","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","provenance":"source","from":"NVD"},"epss":{"score":0.84734,"percentile":0.99707,"date":"2026-10-30","provenance":"source"},"kev":{"dateAdded":"2026-08-31","dueDate":"2026-09-14","ransomware":false,"requiredAction":"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.","notes":"https://www.papercut.com/kb/Main/security-bulletin-27-aug-2026-urgent-security-advisory/ ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk ; https://nvd.nist.gov/vuln/detail/CVE-2026-81578","provenance":"source"},"vulncheckKev":{"dateAdded":"2026-08-28","exploitedFirstSeen":"2026-08-28","ransomware":false,"evidence":[{"url":"https://euvd.enisa.europa.eu/enisa/EUVD-2026-67713","date":"2026-08-28"},{"url":"https://previdian.com/CVE-2026-81578","date":"2026-08-28"},{"url":"https://www.huntress.com/blog/papercut-actively-exploited","date":"2026-08-28"},{"url":"https://www.linkedin.com/posts/yesterday-watchtowr-rapidly-reacted-to-share-7499107361605722112-b2gE/","date":"2026-08-28"},{"url":"https://www.papercut.com/kb/Main/security-bulletin-27-aug-2026-urgent-security-advisory/","date":"2026-08-28"},{"url":"https://x.com/DefusedCyber/status/2094004924660982073","date":"2026-08-30"},{"url":"https://www.acn.gov.it/portale/w/papercut-rilevato-sfruttamento-in-rete-delle-cve-2026-82078-e-cve-2026-81578","date":"2026-08-31"},{"url":"https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json","date":"2026-08-31"},{"url":"https://github.com/rtkwlf/wolf-tools/tree/main/pack_alerts/202609-papercut-cve-exploitation","date":"2026-09-04"},{"url":"https://www.recordedfuture.com/blog/august-2026-cve-landscape","date":"2026-09-08"}],"evidenceTotal":16,"provenance":"source"},"exploited":true,"otx":{"pulseCount":50,"pulses":[{"name":"Actively_Exploited_Kev | Oct 31, 2026","url":"https://otx.alienvault.com/pulse/6ae4aefab0c2191cecd41862","created":"2026-10-30"},{"name":"Actively_Exploited_Kev | Oct 30, 2026","url":"https://otx.alienvault.com/pulse/6ae35d889ea92b4ce19c2680","created":"2026-10-29"},{"name":"Actively_Exploited_Kev | Oct 29, 2026","url":"https://otx.alienvault.com/pulse/6ae20c1db17e7057ae7d9ad1","created":"2026-10-28"},{"name":"EbeeOct2026 Pt5","url":"https://otx.alienvault.com/pulse/6ae189b2042138c108f4126b","created":"2026-10-28"},{"name":"Actively_Exploited_Kev | Oct 28, 2026","url":"https://otx.alienvault.com/pulse/6ae0ba7e0e2a97ff7b218819","created":"2026-10-27"},{"name":"Actively_Exploited_Kev | Oct 27, 2026","url":"https://otx.alienvault.com/pulse/6adf68b85c3e852f3c111d18","created":"2026-10-26"},{"name":"Actively_Exploited_Kev | Oct 24, 2026","url":"https://otx.alienvault.com/pulse/6adb740e397c3ad4799aa4cd","created":"2026-10-23"},{"name":"Actively_Exploited_Kev | Oct 23, 2026","url":"https://otx.alienvault.com/pulse/6ada236fcfba2dfa730ea482","created":"2026-10-22"},{"name":"Inside a PaperCut Attacker's AI Toolkit: Agent Instructions, Exploit Code, a Second RCE, and Victims Across 45+ Countries","url":"https://otx.alienvault.com/pulse/6ad9e638a49d24b258228fa3","created":"2026-10-22"},{"name":"Actively_Exploited_Kev | Oct 22, 2026","url":"https://otx.alienvault.com/pulse/6ad8d33a077cbb5cab524d80","created":"2026-10-21"}],"provenance":"machine"},"cwes":[{"id":"CWE-305","name":"Authentication Bypass by Primary Weakness"},{"id":"CWE-306","name":"Missing Authentication for Critical Functionality"}],"references":[{"url":"https://www.papercut.com/kb/Main/security-bulletin-27-aug-2026-urgent-security-advisory/","tags":["Patch","Vendor Advisory"]},{"url":"https://github.com/rapid7/metasploit-framework/pull/21842","tags":["Issue Tracking","Patch"]},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-81578","tags":["Patch","Third Party Advisory","US Government Resource"]}],"techniques":[{"id":"T1190","name":"Exploit Public-Facing Application","tactics":["initial-access"],"provenance":"ai","basis":"ai-mapping","bases":["ai-mapping"],"basisDetail":"claude-haiku-5-5: unauthenticated remote request to public web interface","mappingType":"exploitation_technique","evidence":[{"from":"description","quote":"unauthenticated remote requests targeting administrative functions","start":139,"end":205}],"model":"claude-haiku-5-5","confidence":"medium","confidenceNote":"AI-mapped from the description (quote-validated, not expert-reviewed)"},{"id":"T1098","name":"Account Manipulation","tactics":["persistence","privilege-escalation"],"provenance":"ai","basis":"ai-mapping","bases":["ai-mapping"],"basisDetail":"claude-haiku-5-5: attacker modifies system configuration settings","mappingType":"primary_impact","evidence":[{"from":"description","quote":"allows an unauthenticated remote attacker to modify certain system configurations","start":293,"end":374}],"model":"claude-haiku-5-5","confidence":"medium","confidenceNote":"AI-mapped from the description (quote-validated, not expert-reviewed)"}],"reports":[{"id":"SRC-54da84d6e2963a55b84e","title":"Notorious Cybercrime Gang, FIN7, Lands Malware in Law Firm","publisher":"esentire.com","url":"https://www.esentire.com/security-advisories/notorious-cybercrime-gang-fin7-lands-malware-in-law-firm-using-fake-legal-complaint-against-jack-daniels-owner-brown-forman-inc","date":null,"mentions":[{"quote":"PaperCut Discloses Zero-Day Vulnerabilities (CVE-2026-82078 and CVE-2026-81578)","start":2768,"end":2847}]}],"affected":[],"advisories":[],"euvd":{"id":"EUVD-2026-67713","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-67713","exploited":true,"exploitedSince":"2026-08-27","provenance":"source"},"exploits":[],"exploitSources":{"pocGithub":{"count":2,"skipped":0,"earliest":"2026-08-29","earliestUrl":"https://github.com/yora1928/PaperCut-CVE-2026-81578-82078","repos":[{"name":"yora1928/PaperCut-CVE-2026-81578-82078","url":"https://github.com/yora1928/PaperCut-CVE-2026-81578-82078","stars":4,"created":"2026-08-29"},{"name":"virologi-info/papercut-toolkit","url":"https://github.com/virologi-info/papercut-toolkit","stars":2,"created":"2026-08-29"}]},"metasploit":[{"name":"PaperCut NG/MF Unauthenticated RCE (CVE-2026-81578 + CVE-2026-82078)","module":"exploit/multi/http/papercut_ng_external_user_lookup_rce","type":"exploit","disclosureDate":"2026-08-27","url":"https://github.com/rapid7/metasploit-framework/blob/master/modules/exploits/multi/http/papercut_ng_external_user_lookup_rce.rb"}],"nuclei":[{"id":"CVE-2026-81578","name":"PaperCut NG/MF <=26.0.4 - Unauthenticated ConfigEditor Access via Tapestry 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