High 8.8Known exploited (CISA KEV)Published Aug 28, 2026

CVE-2026-81578PaperCut MF/NG: Authentication Bypass

Updated under an hour ago (2026-10-19 04:50 UTC)

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It affects PaperCut MF/NG and 2 other products. Add what you run to find out whether that includes you.

CISA lists it as known exploited since Aug 31, 2026; federal agencies had to remediate by Sep 14, 2026. Treat that date as your deadline.

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Every CVE for PaperCut MF/NG

Exploited in the last 30 days

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.

CVSS: 8.8 HIGH (v4.0, CNA)CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:H/VA:L/SC:N/SI:N/SA:N
Weakness (CWE): CWE-305
Known exploited: Added to CISA KEV Aug 31, 2026; federal remediation due Sep 14, 2026Apply 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.
EPSS (exploitation in the next 30 days): 85.58% (percentile 100)
Assigned by: PaperCut
NVD analysis: Analyzed
Record last updated: Sep 13, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

PaperCut PaperCut MF/NG papercut:mf_ng (from the name)	before 24.1.10; from 25.0.0 before 25.0.13; from 26.0.0 before 26.0.5	CNA record
papercut papercut_mf papercut:papercut_mf	before 24.1.9; from 25.0.2 before 25.0.12; from 26.0.2 before 26.0.4	NVD
papercut papercut_ng papercut:papercut_ng	before 24.1.9; from 25.0.2 before 25.0.12; from 26.0.2 before 26.0.4	NVD

References

https://www.papercut.com/kb/Main/security-bulletin-27-aug-2026-urgent-security-advisory/patch, vendor-advisory
https://github.com/rapid7/metasploit-framework/pull/21842issue-tracking, patch
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-81578patch, third-party-advisory, us-government-resource

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.