CVE-2026-81578Known exploitationNetwork attack vectorHinoki check available

Configuration modification via pre-validation administrative requests

Published Aug 28, 2026 · Updated Aug 29, 2026

Improper access control in the PaperCut NG/MF web interface allows remote attackers to modify system configuration without authentication. Administrative requests can trigger backend actions before access validation checks finish, allowing untrusted input to reach protected functions. The Application Server web interface must be network-reachable; the published impact is limited to certain configuration changes.

CVSS severity8.8
High
EPSS probability3.29%
Next 30 days · Sep 16, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Improper access control in the PaperCut NG/MF web interface allows remote attackers to modify system configuration without authentication. Administrative requests can trigger backend actions before access validation checks finish, allowing untrusted input to reach protected functions. The Application Server web interface must be network-reachable; the published impact is limited to certain configuration changes.

The record

CVE
CVE-2026-81578
Published
Aug 28, 2026
Updated
Aug 29, 2026
Vendor
PaperCut
Product
PaperCut NG/MF
Classifications
CWE-306, CWE-305, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 28, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 29, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <24.1.10, 25.0.13, 26.0.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

PaperCut · PaperCut NG/MFversion=0 <24.1.10, 25.0.13, 26.0.5

Published CVSS scores

8.8PaperCutCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:H/VA:L/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationReported
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-306Missing Authentication for Critical Function
CWE-305Authentication Bypass by Primary Weakness
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Reported exploitation

Technologies

Your stack

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Your stack

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