ZeroDay Findings
Sign inSign up

Findings

CVE-2026-81578

PaperCut NG/MF Missing Authentication for Critical Function Vulnerability

Published Aug 28, 2026 · updated Sep 13, 2026 · PaperCut NG/MF

Overview On August 27, 2026, PaperCut Software published an urgent security advisory stating that it is investigating active exploitation of a vulnerability affecting PaperCut NG and PaperCut MF. PaperCut has confirmed customer incidents and is treating the issue as a security emergency. At the initial time of disclosure, the vulnerability had not been assigned a CVE identifier, and PaperCut had not publicly disclosed a CVSS score, vulnerability class, authentication requirements, or the technical details of the exploit path. However on August 28, the vendor assigned CVE-2026-81578 and CVE-202

Timeline

Detection, updates, and resolution for this record.

  1. Aug 28, 2026 · Catalog

    Detected

    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.

  2. Aug 31, 2026 · CISA KEV

    Known exploited

    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

  3. Sep 13, 2026 · Catalog

    Updated

    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.

  4. Sep 14, 2026 · CISA KEV

    Remediation due

    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

Required action

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.

CISA due date Sep 14, 2026

Affected

  • cpe papercut/papercut mfversion unspecified
  • cpe papercut/papercut ngversion unspecified
  • vendor PaperCut NG/MFversion unspecified

Sources

  • CISA KEVCVE-2026-81578

    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.

    cisa.gov
  • CVE.orgCVE-2026-81578

    Official CVE identifier

    cve.org
  • FIRST EPSSCVE-2026-81578

    30-day exploitation probability 85.6%

    first.org
  • Metasploit Modulesexploit_multi/http/papercut_ng_external_user_lookup_rce

    Public module reference (excellent). Module source is not copied into this catalog.

    rapid7.com
  • NIST NVDCVE-2026-81578

    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

    nvd.nist.gov
  • Rapid7 Vulnerability DatabaseCVE-2026-81578

    Overview On August 27, 2026, PaperCut Software published an urgent security advisory stating that it is investigating active exploitation of a vulnerability affecting PaperCut NG and PaperCut MF. PaperCut has confirmed customer incidents and is treating the issue as a security emergency. At the initial time of disclosure, the vulnerability had not been assigned a CVE identifier, and PaperCut had n

    rapid7.com

References