Vulnerability report

Exploited in the wild Confirmed confidence In CISA KEV

CVE-2023-27350

NG

PaperCut / NG · 22.0.5 (Build 63914)

Watch CVE-2023-27350 Browse KEV feed
Severity
CVSS 9.8 · Critical
Confidence
Confirmed
Exploit status
Exploited in the wild
EPSS
100.0%
First observed
—
Last observed
—

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2023-27350 is an unauthenticated vulnerability affecting PaperCut NG. This vulnerability allows remote attackers to bypass authentication on affected installations of PaperCut NG 22.0.5 (Build 63914)....

Is it exploited?

Yes. Previdian tracks this CVE as a known exploited vulnerability. Confidence is confirmed. Listed in CISA KEV. Also confirmed by third-party sources.

Who is affected?

PaperCut / NG 22.0.5 (build 63914).

What should we do?

Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.

Overview

NG

This vulnerability allows remote attackers to bypass authentication on affected installations of PaperCut NG 22.0.5 (Build 63914). Authentication is not required to exploit this vulnerability. The specific flaw exists within the SetupCompleted class.

The issue results from improper access control. An attacker can leverage this vulnerability to bypass authentication and execute arbitrary code in the context of SYSTEM. Was ZDI-CAN-18987.

PaperCut Affected
NG
22.0.5 (Build 63914)
Published
20 Apr 2023
Exploitation Reported
21 Apr 2023
Attack vector
Remote
Complexity
Low
Privileges
None
User interaction
None

Tags

metasploit malware ransomware cisa nuclei_scanner

CVE References

Exploitation evidence

Why Previdian marks this CVE as exploited

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploited in the wild

CISA

Recorded 21 Apr 2023

A trusted third party reported exploitation.

Used in malware

CISA

Recorded 21 Apr 2023

Malware families have been linked to exploitation of this CVE.

Proof of concept available

GitHub

Recorded 21 Apr 2023

Public scanner or PoC coverage increases practical exploitability.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the Previdian Pro API.

Learn about Pro API access
Source Added
CISA First 2023-04-21 00:00 UTC
The Shadowserver 2026-06-13 00:00 UTC
Rapid7 2026-08-28 10:09 UTC

Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Observed signals

Request targets
User-Agents
Callback hosts
0
0
0

Request targets and User-Agents available in Pro. Callback host details available in Enterprise.

Virtual patch status

No Previdian virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.

Learn about virtual patches →

Scanner Artifacts

Scanner and exploit-framework references linked to this CVE.

Scanner Reference Detected
Metasploit https://github.com/rapid7/metasploit-framework/blob/master/modules/exploits/multi/http/papercut_ng_auth_bypass.rb 28 Apr 2025
Nuclei https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2023/CVE-2023-27350.yaml 25 Apr 2025

Risk and context

Severity, weaknesses, and research context

CVSS v3.1

9.8 Critical

Potential damage if exploited. Separate from whether attackers are using it.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS

100.0%

Estimated chance of exploitation in the next 30 days. Previdian's warning comes from evidence, not this score.

Weaknesses

Improper Access Control CWE-284

Recent mention · Rapid7

PaperCut NG/MF Critical Zero-Day Exploited in the Wild

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...

Read full advisory

All CVSS Scores

CVSS v3.1 9.8 Critical

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS v3.0 9.8 Critical

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Potential Proof of Concepts

These PoCs are unverified and could contain malware. Use at your own risk.

PaperCut - Unauthenticated Remote Code Execution

nuclei · Created Unknown

papercut_ng_auth_bypass

metasploit · Created Unknown

Metasploit module for CVE-2023-27350

Timeline

From disclosure to observed exploitation

  1. 10:09 UTC

    KEV confirmed by Rapid7

    Exploitation attested by an external source

  2. 00:00 UTC

    KEV confirmed by The Shadowserver

    Exploitation attested by an external source

  3. 15:02 UTC

    Metasploit module available

    Exploit module available

  4. 15:02 UTC

    Public PoC available

    Public proof-of-concept code published

  5. 00:00 UTC

    Nuclei template available

    Scanner coverage available

  6. 00:00 UTC

    Added to CISA KEV

    Listed in the CISA Known Exploited Vulnerabilities catalog

  7. 00:00 UTC

    First public exploitation report

    Exploit observed in malware

  8. 00:00 UTC

    CVE published

    Vulnerability disclosed publicly

  9. 00:00 UTC

    CVE ID reserved

    Identifier reserved by the CNA

Pro API

Automate this intelligence

Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

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  • Evidence confidence and provenance
  • First-party sensor telemetry
  • PoC and scanner references
  • Affected versions and enrichment
  • Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2023-27350

Free JSON includes basic KEV fields 
{
  "cve_id": "CVE-2023-27350",
  "confidence": "Confirmed",
  "cvss_score": 9.8,
  "cvss_estimated": false,
  "epss_score": 0.99999,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": false
  },
  "sensor_telemetry": { "attempts": 0, "sensors": 0 }
}