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Fencer Vulns
critical 9.8

CVE-2026-81578 kev in the critical feed json

PaperCut MF/NG: Authentication Bypass

published 2026-08-28 2 mo ago modified 2026-09-14 56 d ago also EUVD-2026-67713

cvss
9.8
version 3.1, NVD
cisa kev
Exploited
added 2026-08-31
epss
84.7%
EPSS 84.7% chance of exploitation in 30 days, percentile 99.7%
public exploits
1
Metasploit, plus a Nuclei check

Summary

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.

Patch / fix

cisa 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.

  • PaperCut PaperCut MF/NG 24.1.10, 25.0.13, 26.0.5

Timeline

  1. First public exploit (Metasploit exploit/multi/http/papercut_ng_external_user_lookup_rce)
  2. CISA SSVC: exploitation active
  3. Published
  4. Added to CISA KEV
  5. CISA patch deadline

Known exploited

Added
2 mo ago
Patch by
2026-09-14 (56 d ago)
Ransomware
Not known
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.
Vendor, product
PaperCut, NG/MF
CISA name
PaperCut NG/MF Missing Authentication for Critical Function Vulnerability

CISA SSVC

Exploitation
Active, exploited in the wild
Automatable
yes
Technical impact
partial
Assessed
2 mo ago

Exploit prediction

84.73% chance of exploitation in the next 30 days, higher than 99.7% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

CVSS scores

assigned by version score vector
CNA 4.0 8.8 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
CNA 4.0 8.8 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

  • PaperCut PaperCut MF/NG

Classification

Weakness
  • CWE-305 Authentication Bypass by Primary Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.