CVE-2023-27351

CRITICALNVD 7.59.0▲
EchelonGraph scoreHIGH confidence

Score elevated to 9.0 because this CVE is listed on the CISA Known Exploited Vulnerabilities catalog (added 2026-04-20), indicating real-world exploitation has been confirmed by US federal agencies. NVD baseline CVSS 7.5 retained for reference. Confidence: HIGH.

Triggered by: CISA KEV (actively exploited)
Sources: cisa_kev, epss, ghsa, nvd
Trending — 4 sources updated this weekExploited in the wild
9.0EG
EchelonGraph verdictPatch nowTreat as an emergency — this is being exploited.
  • Actively exploited in the wild (CISA-KEV)
CISA-KEV: ExploitedEPSS PROB: 77%CVSS: 7.5Exploit: cisa kev · ssvc active · kev ransomware · epss top5pct · epss high · public exploitExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
7.5
EG Score
9.0(high)
EG Risk
96(Act)
EG Risk 96/100SSVC: Act

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity90% × 45%
Exploitation100% × 40%
Automatability100% × 15%
Action: Fix now — active exploitation, automatable, high impact.
EPSS PROB
77%
EPSS %ILE
100%
KEV
⚠ Exploited

Published

April 20, 2023

Last Modified

April 21, 2026

Advisory Details (3)

Auto-updated May 20, 2026
⚠️ Active exploitation confirmed. Patch available. Sources: cisa.
cisa Patch Available🔴 Active Exploitation

Known Exploited Vulnerabilities Catalog | CISA

Known Exploited Vulnerabilities Catalog | CISA. Listed in CISA Known Exploited Vulnerabilities catalog.

https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-27351
generic

ZDI-23-232 | Zero Day Initiative

https://www.zerodayinitiative.com/advisories/ZDI-23-232/
generic

URGENT MF/NG vulnerability bulletin (March 2023) | PaperCut

https://www.papercut.com/kb/Main/PO-1216-and-PO-1219

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 45× in last 7d / 231× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 502 total refreshes for this CVE.

  1. 2026-07-30 17:16 UTCEG score recompute
  2. 2026-07-30 17:16 UTCGHSA enrichment
  3. 2026-07-30 16:26 UTCEPSS rescore
  4. 2026-07-30 16:26 UTCEPSS rescore
  5. 2026-07-30 13:34 UTCGHSA enrichment
  6. 2026-07-30 09:52 UTCEG score recompute
  7. 2026-07-30 09:52 UTCGHSA enrichment
  8. 2026-07-30 06:10 UTCGHSA enrichment
  9. 2026-07-30 02:28 UTCGHSA enrichment
  10. 2026-07-29 22:44 UTCGHSA enrichment
  11. 2026-07-29 19:27 UTCCISA KEV update
  12. 2026-07-29 18:58 UTCGHSA enrichment
  13. 2026-07-29 15:16 UTCGHSA enrichment
  14. 2026-07-29 11:34 UTCGHSA enrichment
  15. 2026-07-29 07:51 UTCGHSA enrichment
  16. 2026-07-29 04:08 UTCGHSA enrichment
  17. 2026-07-29 00:26 UTCGHSA enrichment
  18. 2026-07-28 20:43 UTCGHSA enrichment
  19. 2026-07-28 17:01 UTCEG score recompute
  20. 2026-07-28 17:01 UTCGHSA enrichment
  21. 2026-07-28 15:34 UTCEPSS rescore
  22. 2026-07-28 15:34 UTCEPSS rescore
  23. 2026-07-28 13:19 UTCGHSA enrichment
  24. 2026-07-28 09:37 UTCGHSA enrichment
  25. 2026-07-28 05:52 UTCGHSA enrichment
Show 75 more
  1. 2026-07-28 02:09 UTCGHSA enrichment
  2. 2026-07-27 22:26 UTCGHSA enrichment
  3. 2026-07-27 19:24 UTCCISA KEV update
  4. 2026-07-27 18:44 UTCGHSA enrichment
  5. 2026-07-27 17:17 UTCCISA KEV update
  6. 2026-07-27 15:02 UTCGHSA enrichment
  7. 2026-07-27 11:20 UTCGHSA enrichment
  8. 2026-07-27 07:38 UTCGHSA enrichment
  9. 2026-07-27 03:55 UTCGHSA enrichment
  10. 2026-07-27 00:12 UTCGHSA enrichment
  11. 2026-07-26 20:30 UTCGHSA enrichment
  12. 2026-07-26 16:47 UTCGHSA enrichment
  13. 2026-07-26 13:05 UTCEG score recompute
  14. 2026-07-26 13:05 UTCGHSA enrichment
  15. 2026-07-26 09:22 UTCGHSA enrichment
  16. 2026-07-26 05:40 UTCGHSA enrichment
  17. 2026-07-26 01:57 UTCEG score recompute
  18. 2026-07-26 01:57 UTCGHSA enrichment
  19. 2026-07-25 14:16 UTCEPSS rescore
  20. 2026-07-24 14:15 UTCEPSS rescore
  21. 2026-07-23 02:20 UTCEG score recompute
  22. 2026-07-22 23:39 UTCEG score recompute
  23. 2026-07-22 23:39 UTCGHSA enrichment
  24. 2026-07-22 23:08 UTCEG score recompute
  25. 2026-07-22 19:56 UTCGHSA enrichment
  26. 2026-07-22 19:40 UTCCISA KEV update
  27. 2026-07-22 16:14 UTCEG score recompute
  28. 2026-07-22 16:13 UTCGHSA enrichment
  29. 2026-07-22 14:06 UTCEPSS rescore
  30. 2026-07-22 14:06 UTCEPSS rescore
  31. 2026-07-22 12:29 UTCGHSA enrichment
  32. 2026-07-22 08:47 UTCGHSA enrichment
  33. 2026-07-22 05:04 UTCGHSA enrichment
  34. 2026-07-22 01:21 UTCGHSA enrichment
  35. 2026-07-21 21:37 UTCGHSA enrichment
  36. 2026-07-21 17:55 UTCEG score recompute
  37. 2026-07-21 17:55 UTCGHSA enrichment
  38. 2026-07-21 15:23 UTCEPSS rescore
  39. 2026-07-21 14:37 UTCCISA KEV update
  40. 2026-07-21 14:13 UTCGHSA enrichment
  41. 2026-07-21 10:31 UTCGHSA enrichment
  42. 2026-07-21 06:48 UTCGHSA enrichment
  43. 2026-07-21 03:05 UTCGHSA enrichment
  44. 2026-07-20 23:21 UTCGHSA enrichment
  45. 2026-07-20 19:39 UTCEG score recompute
  46. 2026-07-20 19:39 UTCGHSA enrichment
  47. 2026-07-20 17:06 UTCEPSS rescore
  48. 2026-07-20 15:57 UTCGHSA enrichment
  49. 2026-07-20 12:14 UTCGHSA enrichment
  50. 2026-07-20 08:31 UTCGHSA enrichment
  51. 2026-07-20 04:49 UTCGHSA enrichment
  52. 2026-07-19 21:24 UTCGHSA enrichment
  53. 2026-07-19 17:42 UTCEG score recompute
  54. 2026-07-19 17:42 UTCGHSA enrichment
  55. 2026-07-19 14:29 UTCEPSS rescore
  56. 2026-07-19 14:29 UTCEPSS rescore
  57. 2026-07-19 14:00 UTCGHSA enrichment
  58. 2026-07-19 10:18 UTCGHSA enrichment
  59. 2026-07-19 06:36 UTCGHSA enrichment
  60. 2026-07-19 02:53 UTCEG score recompute
  61. 2026-07-19 02:53 UTCGHSA enrichment
  62. 2026-07-19 02:27 UTCEPSS rescore
  63. 2026-07-19 02:27 UTCEPSS rescore
  64. 2026-07-18 23:10 UTCGHSA enrichment
  65. 2026-07-18 19:28 UTCGHSA enrichment
  66. 2026-07-18 15:45 UTCGHSA enrichment
  67. 2026-07-18 12:03 UTCEG score recompute
  68. 2026-07-18 12:02 UTCGHSA enrichment
  69. 2026-07-18 10:03 UTCEPSS rescore
  70. 2026-07-18 10:03 UTCEPSS rescore
  71. 2026-07-18 08:19 UTCGHSA enrichment
  72. 2026-07-18 04:37 UTCGHSA enrichment
  73. 2026-07-18 00:55 UTCGHSA enrichment
  74. 2026-07-17 21:13 UTCGHSA enrichment
  75. 2026-07-17 17:31 UTCGHSA enrichment

Publicly available exploits

(1 reference)

Working exploit code is in the public domain. Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • Nucleihttp/cves/2023/CVE-2023-27351.yaml
    First seen Jan 1, 2023

    PaperCut NG - Authentication Bypass

    Open source ↗

Frequently asked(6)

What is CVE-2023-27351?
CVE-2023-27351 is a critical vulnerability published on April 20, 2023. 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…
When was CVE-2023-27351 disclosed?
CVE-2023-27351 was first published in the National Vulnerability Database on April 20, 2023, with the most recent update on April 21, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2023-27351 actively exploited?
Yes. CISA added CVE-2023-27351 to the Known Exploited Vulnerabilities catalog on April 20, 2026, affecting PaperCut NG/MF. KEV listing indicates confirmed exploitation in the wild; this CVE warrants immediate patching attention.
What is the CVSS score of CVE-2023-27351?
CVE-2023-27351 has a CVSS v3 base score of 7.5 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 9.0.
Which products are affected by CVE-2023-27351?
CVE-2023-27351 affects PaperCut NG/MF. The full affected-products list, including version ranges and fixed versions, is shown in the Affected Packages section of this page.
How do I remediate CVE-2023-27351?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2023-27351, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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