CVE-2020-29583

CRITICALNVD 9.89.8—
EchelonGraph scoreHIGH confidence

Score elevated to 9.8 because this CVE is listed on the CISA Known Exploited Vulnerabilities catalog (added 2021-11-03), indicating real-world exploitation has been confirmed by US federal agencies. NVD baseline CVSS 9.8 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
9.8
EchelonGraph verdictPatch nowTreat as an emergency — this is being exploited.
  • Actively exploited in the wild (CISA-KEV)
CISA-KEV: ExploitedEPSS: 90%CVSS: 9.8Exploit: NoneExposed: 0

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

Firmware version 4.60 of Zyxel USG devices contains an undocumented account (zyfwp) with an unchangeable password. The password for this account can be found in cleartext in the firmware. This account can be used by someone to login to the ssh server or web interface with admin privileges.

CVSS v3
9.8
EG Score
9.8(high)
EG Risk
99(Act)
EG Risk 99/100SSVC: 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
Severity98% × 45%
Exploitation100% × 40%
Automatability100% × 15%
Action: Fix now — active exploitation, automatable, high impact.
EPSS
99.8%
KEV
⚠ Exploited

Published

December 22, 2020

Last Modified

November 7, 2025

Advisory Details (5)

Auto-updated Jun 1, 2026
No patch confirmed yet.
generic

What's New for ZLD4.60 patch 1 (available on Dec. 15) - Page 2 — Zyxel Community

https://businessforum.zyxel.com/discussion/5254/whats-new-for-zld4-60-patch-1-available-on-dec-15
generic

ZLD v4.60 Revoke and WK48 Firmware release — Zyxel Community

https://businessforum.zyxel.com/discussion/5252/zld-v4-60-revoke-and-wk48-firmware-release
generic

Support Download Page Redirect

https://www.zyxel.com/support/security_advisories.shtml
generic

Support Download Page Redirect

https://www.zyxel.com/support/CVE-2020-29583.shtml
generic

Secret Backdoor to Zyxel Firewall and AP Controllers Could Allow Admin | SecPod

https://www.secpod.com/blog/a-secret-zyxel-firewall-and-ap-controllers-could-allow-for-administrative-access-cve-2020-29583/

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 46× in last 7d / 197× 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 360 total refreshes for this CVE.

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

Publicly available exploits

(2 references)

Working exploit code is in the public domain (1 GitHub PoC). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • GitHub PoCruppde/scan_CVE-2020-29583
    First seen Jan 4, 2021

    Scanner for Zyxel products which are potentially vulnerable due to an undocumented user account (CVE-2020-29583)

    Open source ↗
  • Nucleihttp/cves/2020/CVE-2020-29583.yaml
    First seen Jan 1, 2020

    ZyXel USG - Hardcoded Credentials

    Open source ↗

Frequently asked(6)

What is CVE-2020-29583?
CVE-2020-29583 is a critical vulnerability published on December 22, 2020. Firmware version 4.60 of Zyxel USG devices contains an undocumented account (zyfwp) with an unchangeable password. The password for this account can be found in cleartext in the firmware. This account can be used by someone to login to the ssh server or web interface with admin privileges.
When was CVE-2020-29583 disclosed?
CVE-2020-29583 was first published in the National Vulnerability Database on December 22, 2020, with the most recent update on November 7, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2020-29583 actively exploited?
Yes. CISA added CVE-2020-29583 to the Known Exploited Vulnerabilities catalog on November 3, 2021, affecting Zyxel Multiple Products. KEV listing indicates confirmed exploitation in the wild; this CVE warrants immediate patching attention.
What is the CVSS score of CVE-2020-29583?
CVE-2020-29583 has a CVSS v3 base score of 9.8 (NVD).
Which products are affected by CVE-2020-29583?
CVE-2020-29583 affects Zyxel Multiple Products. 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-2020-29583?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2020-29583, 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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