Exploited Ransomware

CVE-2023-27350

PaperCut NG / MF · Office, PDF and utilities

PaperCut MF/NG Improper Access Control Vulnerability

At a glance

Exploited. Added to CISA’s catalog of exploited vulnerabilities on April 21, 2023.

Used in ransomware attacks, according to CISA.

Affected product: PaperCut NG / MF (category Office, PDF and utilities, indicative classification). Name in CISA’s catalog: PaperCut MF/NG.

What should I do?

Apply the security update from PaperCut.

Deadline set by CISA for US federal agencies: 21 days (due May 12, 2023). It only binds those agencies, but it is a useful measure of urgency.

PaperCut security advisories page (general page, not the advisory for this vulnerability)
The vendor’s specific advisory is listed in the NVD references: CVE-2023-27350 on the NVD website.

Original text of the required action (CISA)

Apply updates per vendor instructions.

Timeline

April 20, 2023 Vulnerability published Publication date (NVD)
April 21, 2023 Exploitation confirmed Added to CISA’s KEV catalog
May 12, 2023 CISA deadline Remediation deadline set for US federal agencies

The facts, with their sources

Exploitation confirmed: Yes, on April 21, 2023 Date added to the catalog of exploited vulnerabilities. Exploitation itself may have started earlier. Source: KEV catalog, collected September 29, 2026 at 11:25 UTC
Ransomware: Known use Source: KEV catalog, collected September 29, 2026 at 11:25 UTC
Hunt for compromise: Not requested by CISA Source: KEV catalog, collected September 29, 2026 at 11:25 UTC
CISA required action: Apply the security update from PaperCut. Rewritten by this site from CISA’s original text. Source: KEV catalog, collected September 29, 2026 at 11:25 UTC
CISA deadline: May 12, 2023, 21 days Set for US federal agencies: a measure of urgency, not an obligation elsewhere. Source: KEV catalog, collected September 29, 2026 at 11:25 UTC
Vulnerability published: April 20, 2023 Source: National Vulnerability Database (NVD), collected September 29, 2026 at 11:29 UTC
Product according to CISA: PaperCut MF/NG Filed by this site under “Office, PDF and utilities” (indicative classification). Source: KEV catalog, collected September 29, 2026 at 11:25 UTC
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Technical detail of the score: attack vector, complexity, impact. Source: National Vulnerability Database (NVD), collected September 29, 2026 at 11:29 UTC

Severity and activity

9.8 / 10 CVSS severity: critical

Score from the NVD. Collected Sep 29, 2026.

— Probability of exploitation in the next 30 days (EPSS)

FIRST’s EPSS model. Since exploitation is already confirmed, this figure is mostly useful to compare activity. Collected Sep 29, 2026.

Description

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 MF/NG contains an improper access control vulnerability within the SetupCompleted class that allows authentication bypass and code execution in the context of system.

Summary from CISA (KEV catalog).

CERT-FR advisories

No advisory among the latest CERT-FR publications this site follows. That does not mean there are none.

Information reused under the Open Licence 2.0 (Etalab); the date of last update is shown for each advisory. This site is neither affiliated with nor endorsed by ANSSI.

Sources for this page

CISA KEV catalog: exploitation, date added, required action, deadline, ransomware.
NVD (NIST): CVSS severity, publication date, description, vendor references.
EPSS (FIRST): probability of exploitation.
CERT-FR: advisories and alerts (in French).
Brand and category: indicative classification by this site (method).