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Vulnerabilities/CVE-2023-27351Public Intelligence Dossier
Source: papercut · Limited verification•Last verified: •Collection Degraded
CVE-2023-27351ListedHIGH (raw)CVSS 8.2CWE-287

This vulnerability allows remote attackers to bypass authentication on affected installations of PaperCut NG 22.0.5 (Build 63914)

Published: 20 Apr 2023•Last updated: 02 Oct 2026, 12:47 AM IST•Source identifier: zdi-disclosures@trendmicro.com
Dossier completeness: source-provided sections 3 / 3 · rule guidance available. Missing source facts count as incomplete.
Official source
CISA KEV catalog
Listed
Added20 Apr 2026
Due04 May 2026
RansomwareKnown
CVSS score
8.2HIGH (raw)
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N
Metric sourcezdi-disclosures@trendmicro.com
EPSS probability
78.1%0.781
Percentile100th
Weakness type
CWE-287
No further CWE recorded
Remediation
Patch status unknown
No fixed version or KB recorded

Why It Matters

Analysis dossier

Why It Matters

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.

SOC priority

Immediate Attention

Actively exploited

Yes

Publicly disclosed

Unknown

Risk basis: CISA KEV exploitation signal; HIGH severity; Known exploitation signal from CISA KEV or ransomware metadata

Affected Products & Remediation

2 source-backed products
Affected products and versions (source)
  • papercut papercut mf · >= 15.0 < 20.1.7; >= 21.0.0 < 21.2.11; >= 22.0.0 < 22.0.9 · NVD CPE · Source
  • papercut papercut ng · >= 15.0 < 20.1.7; >= 21.0.0 < 21.2.11; >= 22.0.0 < 22.0.9 · NVD CPE · Source
Recorded patch / KBNot provided by source

Vendor or catalog guidance (source)

  • CISA KEV: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Known exploitation (source facts)

Only what a source states. Unknown means no source has said either way; it is not "not exploited".

CISA KEV
Listed
Exploited (source statement)
Yes
Publicly disclosed (source)
Unknown

CISA required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Suggested hunting (rule-based inference)

SecOps Signal recommendation (rule-based inference). These steps are hunting hypotheses from the vulnerability class; they do not state or imply that exploitation occurred here or anywhere.

Matched kev-network-exposure (CVSS AV:N, CISA KEV Listed); authentication-weakness (CWE-287)

Exposure

  1. Identify assets with the exact CVE and confirm the affected product/version against the advisory.Telemetry: DeviceTvmSoftwareVulnerabilities · KEV listing raises urgency, but inventory is needed to establish local exposure. · Rule kev-network-exposure
  2. Identify affected authentication surfaces and compare versions with the advisory.Telemetry: Application inventory · A CWE match is not proof of local exposure. · Rule authentication-weakness

Exploitation evidence

  1. Review relevant edge or application access logs for unusual requests around the advisory window.Telemetry: CommonSecurityLog · Log review is a hunting hypothesis; KEV listing alone does not show local exploitation. · Rule kev-network-exposure
Show more (2)

Exploitation evidence

  1. Review unexpected successful sign-ins and changes to privileged accounts on affected systems.Telemetry: SigninLogs · Access anomalies are relevant to authentication weaknesses. · Rule authentication-weakness

Response

  1. Recheck the affected assets after the source-stated mitigation or update is applied.Telemetry: DeviceTvmSoftwareVulnerabilities · A follow-up inventory check verifies local remediation. · Rule kev-network-exposure

CISA KEV Record

Catalog entry
20 Apr 2026
Required action due
04 May 2026
Known ransomware use
Known

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Change History & Source Data

— No recorded material change

CNA / source
zdi-disclosures@trendmicro.com
Record status · verification
UPDATED · CISA KEV confirmed
CPE
cpe:2.3:a:papercut:papercut_mf:*:*:*:*:*:*:*:*, cpe:2.3:a:papercut:papercut_ng:*:*:*:*:*:*:*:*

Evidence & Provenance

4 public sources
CISA KEV CatalogAdded 2026-04-20papercut.comSource recordnvd.nist.govSource recordzerodayinitiative.comSource record

Linked by the query's stored exact CVE association. Review required tables and validation status before use.

Detection Hunting Query
Target: DeviceTvmSoftwareVulnerabilities•Defender XDR
Detect endpoints exposed to CVE-2023-27351
Purpose: Exposure assessment (Category: Exposure Check)Why linked: Query metadata names CVE-2023-27351
DeviceTvmSoftwareVulnerabilities| where CveId == "CVE-2023-27351"| project DeviceId, DeviceName, OSPlatform, OSVersion, SoftwareVendor, SoftwareName, SoftwareVersion, CveId, VulnerabilitySeverityLevel, RecommendedSecurityUpdate, RecommendedSecurityUpdateId| sort by VulnerabilitySeverityLevel desc
Schema Checked · Not runtime validatedSource: SecOps Signal deterministic template · Limited verificationStatic screening: Passed structure and schema checks; tenant execution is not verified.
Open KQL Library
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Correlated briefings

SecOps Signal surfaces public advisory facts only. A missing value means the source has not published it, not that your environment is unaffected. No tenant inventory is connected.