CVE-2023-27351 (GCVE-0-2023-27351)
Vulnerability from cvelistv5 – Published: 2023-04-20 00:00 – Updated: 2026-10-01 18:09Summary
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.
Severity
8.2 (High)
SSVC
Exploitation: active
Automatable: yes
Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-04-21 03:55 UTC
CWE
- CWE-287 - Improper Authentication
Assigner
References
3 references
CISA
Known Exploited Vulnerability - GCVE BCP-07 Compliant
KEV entry ID: 4b24ab58-96c9-405f-8350-3f4e1ba3a1bf
Exploited: Yes
Timestamps
First Seen: 2026-04-20
Asserted: 2026-04-20
Scope
Notes: PaperCut NG/MF Improper Authentication Vulnerability | Affected: PaperCut / NG/MF | Description: PaperCut NG/MF contains an improper authentication vulnerability that could allow remote attackers to bypass authentication on affected installations via the SecurityRequestFilter class. | 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. | Due date: 2026-05-04 | Known ransomware campaign use (KEV): Known | Notes (KEV): https://www.papercut.com/kb/Main/PO-1216-and-PO-1219 ; https://nvd.nist.gov/vuln/detail/CVE-2023-27351
Evidence
Type: Vendor Report
Signal: Successful Exploitation
Confidence: 80%
Source: cisa-kev
Details
| Cwes | CWE-287 |
|---|---|
| Feed | CISA Known Exploited Vulnerabilities Catalog |
| Product | NG/MF |
| Due Date | 2026-05-04 |
| Date Added | 2026-04-20 |
| Vendorproject | PaperCut |
| Vulnerabilityname | PaperCut NG/MF Improper Authentication Vulnerability |
| Knownransomwarecampaignuse | Known |
References
Created: 2026-10-02 08:09 CEST
| Updated: 2026-10-02 08:09 CEST
Previdian
Known Exploited Vulnerability - GCVE BCP-07 Compliant
KEV entry ID: 64db0bc9-4d38-4f89-85ce-ec95a7dcb7f9
Exploited: Yes
Timestamps
First Seen: 2026-06-01
Asserted: 2026-06-01
Scope
Notes: This vulnerability allows remote attackers to bypass authentication on affected installations of PaperCut NG 22.0.5 (Build 63914). Authentication... | Affected: PaperCut / NG | CVSS: 7.5 (HIGH) | EPSS: 0.78052 | Used in malware: yes | Listed 1 day ahead of CISA KEV | Not yet in CISA KEV: False
Evidence
Type: Public Report
Signal: Confirmed Compromise
Confidence: 70%
Source: previdian
Details
| Feed | Previdian (previdian.com) |
|---|---|
| Title | This vulnerability allows remote attackers to bypass authentication on affected installations of PaperCut NG 22.0.5 (Build 63914). Authentication... |
| Cve Id | CVE-2023-27351 |
| Vendor | PaperCut |
| Ghsa Id | None |
| Product | NG |
| Added Date | 2026-06-01T13:22:22.013Z |
| Cvss Score | 7.5 |
| Epss Score | 0.78052 |
| Previous Ids | |
| Cvss Severity | HIGH |
| Virtual Patch | False |
| Cvss Estimated | False |
| Epss Percentile | 0.99564 |
| Used In Malware | yes |
| Vulnerability Id | CVE-2023-27351 |
| Ahead Of Cisa Kev |
|
| Not Yet In Cisa Kev | False |
References
Created: 2026-10-02 09:09 CEST
| Updated: 2026-10-02 09:09 CEST
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
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