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CVE-2023-27351

HIGH 7.5 KNOWN EXPLOITED RANSOMWARE DETECTION TEMPLATE ALL-YEARS

Published 2023-04-20 · Last modified 2026-10-01 · zdi · NVD: Analyzed

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.

ACTIVELY EXPLOITED

Confirmed exploited in the wild — in CISA KEV since 2026-04-20, linked to ransomware campaigns. Patch or mitigate now.

Exploitation likelihood

78.1%chance of exploitation in 30 days · 100th percentile

● In CISA KEV (2026-04-20)○ Catalogued PoC◆ SSVC: exploitation active, automatable yes

Impact if exploited

7.5CVSS 3.1 · HIGH · NVD

  • ConfidentialityHigh
  • IntegrityNone
  • AvailabilityNone

What an attacker needs

  • ✓Access: Reachable over the network — no local access needed
  • ✓Privileges: No account or privileges required
  • ✓User interaction: No user interaction needed
  • ✓Complexity: No special conditions — reliably repeatable

✓ lowers the bar for an attacker · ⚠ raises it

Proof of concept

No public PoC is currently catalogued.

Detection templates

Detection checks are listed separately from PoCs.

Resource commands

nuclei -id CVE-2023-27351 -u https://TARGETDetection template — review its checks and affected versions before use.

Search for new PoCs

Search GitHub now — results may be empty or unverified.

Tracked sources are checked weekly for the full archive, including PoCs published after the original disclosure. A later release appears after a tracked source lists it and a refresh succeeds.

Data snapshot:

Affected

Vendors Papercut

Products Ng Papercut Mf Papercut Ng

Weakness (CWE)

  • CWE-287: : Improper Authentication

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

References and research data (JSON)

Additional exploitation reports

Source-specific reports, separate from CISA KEV. Repeated observations from one source are not independent confirmations.

98 more source reports

Known Affected Software Configurations

VendorProductVersion range
PapercutPapercut Mf≥ 15.0 and < 20.1.7
PapercutPapercut Mf≥ 21.0.0 and < 21.2.11
PapercutPapercut Mf≥ 22.0.0 and < 22.0.9
PapercutPapercut Ng≥ 15.0 and < 20.1.7
PapercutPapercut Ng≥ 21.0.0 and < 21.2.11
PapercutPapercut Ng≥ 22.0.0 and < 22.0.9

All CVSS metrics

  • HIGH 8.2 v3.0 · CNA Primary
    CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N
  • HIGH 7.5 v3.1 · NVD Primary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
  • HIGH 8.2 v3.0 · NVD Secondary
    CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N

References

Advisories

Technical & other

Sources: NVD · CVE.org · All sources and attribution · EPSS