Background exploitation KEV catalog Ransomware No authentication

CVE-2023-27350

PaperCut MF/NG Improper Access Control Vulnerability

CheckOps priority index

9.9/10 Patch within 24 h

Severity9.8

Probability10.0

Exploitation5/5

Severity = CVSS. Probability = EPSS (FIRST). Exploitation = public signals: KEV, EUVD, ransomware, EPSS above 10 %, no account required.

EPSS · today 100.00% higher than 99.99% of CVEs

CVSS 3.0 9.8 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:

Exploited for 1,292 days 21 Apr 2023

CISA due date 12 May 2023 for US federal agencies

Exploitation probability EPSS · FIRST

EPSS probability (%)Percentile among all CVEs

Exploitation signals 5 / 5

KEV catalog (CISA)21 Apr 2023
Exploited in EUVD (ENISA)21 Apr 2023
Used by ransomwareyes
EPSS above 10 %100.00%
No account, over the networkyes

What to do

Fix

Apply the vendor’s fix as soon as it is available.

CISA guidance: Apply updates per vendor instructions.

Meanwhile

Take the service off the internet or restrict access to it, watch the logs and look for signs of compromise.

Manufacturers (CRA)

Exploited vulnerability in your product: early warning to ENISA within 24 h, then notification within 72 h (Article 14 of the Cyber Resilience Act). The CRA explained

Description ENISA EUVD

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.

Affected products

NGMF/NG

Affected versions

22.0.5 (Build 63914)

Weaknesses (CWE)

CWE-284

Open source packages OSV

Affected libraries according to OSV, with fixed versions.

Timeline

20 Apr 2023
Published
21 Apr 2023
Exploitation reported (ENISA)
21 Apr 2023
Added to the KEV catalog
12 May 2023
CISA remediation due date
26 Sept 2026
EPSS peak: 100.00%

References

Other exploited vulnerabilities from the same vendor

CVE-2026-82078PaperCut NG/MF Unsafe Reflection Vulnerability
7.5 · Actively exploited
CVE-2026-81578PaperCut NG/MF Missing Authentication for Critical Function Vulnerability
8.5 · Actively exploited
CVE-2023-27351PaperCut NG/MF Improper Authentication Vulnerability
8.6 · Background exploitation
CVE-2023-2533PaperCut NG/MF Cross-Site Request Forgery (CSRF) Vulnerability
6.0 · Background exploitation