CVE-2021-40859

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.8 under NVD CVSS v3. EPSS exploit probability: 72.0%, top 1% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
Elevated
9.8EG
EchelonGraph verdictPatch this weekExploitation is likely or a public exploit exists.
  • High exploitation likelihood — EPSS 72%
CISA-KEV: Not listedEPSS PROB: 72%CVSS: 9.8Exploit: Elevated riskExposed: 0

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

Backdoors were discovered in Auerswald COMpact 5500R 7.8A and 8.0B devices, that allow attackers with access to the web based management application full administrative access to the device.

CVSS v3
9.8
EG Score
9.8(medium)
EG Risk
77(Track*)
EG Risk 77/100SSVC: Track*

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%
Exploitation72% × 40%
Automatability30% × 15%
Action: Watch closely — could escalate to Attend.
EPSS PROB
72%
EPSS %ILE
99%
KEV
Not listed

Published

December 7, 2021

Last Modified

November 21, 2024

Advisory Details (2)

Auto-updated Sep 4, 2026
🔬 Proof of concept available. No patch confirmed yet.
generic🟡 PoC Available

Auerswald COMpact Multiple Backdoors - RedTeam Pentesting

https://www.redteam-pentesting.de/en/advisories/rt-sa-2021-007/-auerswald-compact-multiple-backdoors
generic

Advisories - RedTeam Pentesting

https://www.redteam-pentesting.de/en/advisories/-advisories-publicised-vulnerability-analyses

Data Freshness Timeline

(refreshed 4× in last 7d / 21× 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.

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

Publicly available exploits

(4 references)

Working exploit code is in the public domain (2 GitHub PoCs) (1 Exploit-DB entry). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • GitHub PoCpussycat0x/CVE-2021-40859
    First seen Dec 29, 2021

    Auerswald VoIP System Secret Backdoors -PoC

    Open source ↗
  • GitHub PoC419066074/CVE-2021-40859
    First seen Dec 28, 2021

    Auerswald COMpact 8.0B Backdoors exploit

    Open source ↗
  • Exploit-DBEDB-50569
    First seen Dec 6, 2021

    Auerswald COMpact 8.0B - Multiple Backdoors

    Open source ↗
  • Nucleihttp/cves/2021/CVE-2021-40859.yaml
    First seen Jan 1, 2021

    Auerswald COMpact 5500R 7.8A and 8.0B Devices Backdoor

    Open source ↗

Frequently asked(5)

What is CVE-2021-40859?
CVE-2021-40859 is a critical vulnerability published on December 7, 2021. Backdoors were discovered in Auerswald COMpact 5500R 7.8A and 8.0B devices, that allow attackers with access to the web based management application full administrative access to the device.
When was CVE-2021-40859 disclosed?
CVE-2021-40859 was first published in the National Vulnerability Database on December 7, 2021, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-40859 actively exploited?
CVE-2021-40859 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 72% probability of exploitation in the next 30 days, which ranks it in the top 0.6% of all scored CVEs.
What is the CVSS score of CVE-2021-40859?
CVE-2021-40859 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2021-40859?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-40859, 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

Explore the affected products and dependency analysis for CVE-2021-40859

Explore →

Is Your Infrastructure Affected by CVE-2021-40859?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs