How severe is CVE-2023-27351?

CVE-2023-27351 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2023-27351 being actively exploited?

Yes. CVE-2023-27351 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2026-04-20, which means active exploitation has been confirmed. It should be prioritised for remediation.

What products are affected by CVE-2023-27351?

CVE-2023-27351 primarily affects Papercut Papercut Mf. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2023-27351?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.

Does CVE-2023-27351 have an EU (EUVD) identifier?

Yes. CVE-2023-27351 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2023-31127. It is also flagged as exploited in the EUVD (since 2026-04-20).

When was CVE-2023-27351 published?

CVE-2023-27351 was published on 2023-04-20 and last updated on 2026-10-01.

CVE-2023-27351

CVE-2023-27351 is a high-severity vulnerability in Papercut Papercut Mf with a CVSS 3.x base score of 7.5. It is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, confirming it has been exploited in the wild (added 2026-04-20). The underlying weakness is classified as CWE-287.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 78% (100th percentile)
Actively exploited: Yes — listed in CISA KEV (added 2026-04-20)
EU (EUVD) id: EUVD-2023-31127
EU exploitation: Flagged exploited in the ENISA EU Vulnerability Database (since 2026-04-20)
Weakness: CWE-287
Affected product: Papercut Papercut Mf
Published: 2023-04-20
Last modified: 2026-10-01

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 SecurityRequestFilter class. The issue results from improper implementation of the authentication algorithm. An attacker can leverage this vulnerability to bypass authentication on the system. Was ZDI-CAN-19226.

Frequently asked questions

What is CVE-2023-27351?: 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 SecurityRequestFilter class. The issue results from improper implementation of the authentication algorithm. An attacker can leverage this vulnerability to bypass authentication on the system. Was ZDI-CAN-19226.
How severe is CVE-2023-27351?: CVE-2023-27351 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2023-27351 being actively exploited?: Yes. CVE-2023-27351 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2026-04-20, which means active exploitation has been confirmed. It should be prioritised for remediation.
What products are affected by CVE-2023-27351?: CVE-2023-27351 primarily affects Papercut Papercut Mf. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2023-27351?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.
Does CVE-2023-27351 have an EU (EUVD) identifier?: Yes. CVE-2023-27351 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2023-31127. It is also flagged as exploited in the EUVD (since 2026-04-20).
When was CVE-2023-27351 published?: CVE-2023-27351 was published on 2023-04-20 and last updated on 2026-10-01.

References

Affected products (2)

cpe:2.3:a:papercut:papercut_mf:*:*:*:*:*:*:*:*
cpe:2.3:a:papercut:papercut_ng:*:*:*:*:*:*:*:*

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