CVE-2021-40856

HIGHNVD 7.59.0▲
EchelonGraph scoreHIGH confidence

Score elevated to 9.0 because EPSS predicts 88% probability of exploitation within the next 30 days (top 0.5% of all CVEs). NVD baseline CVSS 7.5 retained for reference. Confidence: see factors.

Triggered by: EPSS exploit prediction ≥85%
Sources: epss, ghsa, nvd
Elevated
7.5
EchelonGraph verdictPatch this weekExploitation is likely or a public exploit exists.
  • High exploitation likelihood — EPSS 51%
CISA-KEV: Not listedEPSS: 51%CVSS: 7.5Exploit: NoneExposed: 0

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

Auerswald COMfortel 1400 IP and 2600 IP before 2.8G devices allow Authentication Bypass via the /about/../ substring.

CVSS v3
7.5
EG Score
9.0(high)
EPSS
98.8%
KEV
Not listed

Published

December 13, 2021

Last Modified

November 21, 2024

References (6)

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 7× in last 7d / 37× 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. 2026-07-22 14:06 UTCEPSS rescore
  2. 2026-07-21 15:22 UTCEPSS rescore
  3. 2026-07-21 15:22 UTCEPSS rescore
  4. 2026-07-20 17:05 UTCEPSS rescore
  5. 2026-07-19 02:27 UTCEPSS rescore
  6. 2026-07-16 17:00 UTCEPSS rescore
  7. 2026-07-16 17:00 UTCEPSS rescore
  8. 2026-07-15 16:55 UTCEPSS rescore
  9. 2026-07-15 16:55 UTCEPSS rescore
  10. 2026-07-15 01:58 UTCEPSS rescore
  11. 2026-07-13 22:27 UTCEPSS rescore
  12. 2026-07-13 22:27 UTCEPSS rescore
  13. 2026-07-13 06:11 UTCEPSS rescore
  14. 2026-07-13 06:11 UTCEPSS rescore
  15. 2026-07-12 05:44 UTCEPSS rescore
  16. 2026-07-11 08:25 UTCEPSS rescore
  17. 2026-07-11 08:25 UTCEPSS rescore
  18. 2026-07-09 19:07 UTCEPSS rescore
  19. 2026-07-08 15:12 UTCEPSS rescore
  20. 2026-07-05 02:28 UTCEPSS rescore
  21. 2026-07-05 02:28 UTCEPSS rescore
  22. 2026-07-04 06:29 UTCEPSS rescore
  23. 2026-07-04 06:29 UTCEPSS rescore
  24. 2026-07-02 16:57 UTCEPSS rescore
  25. 2026-07-01 15:04 UTCEPSS rescore
Show 46 more
  1. 2026-06-30 23:20 UTCEPSS rescore
  2. 2026-06-30 23:20 UTCEPSS rescore
  3. 2026-06-28 04:54 UTCEPSS rescore
  4. 2026-06-28 04:54 UTCEPSS rescore
  5. 2026-06-27 03:06 UTCEPSS rescore
  6. 2026-06-27 03:06 UTCEPSS rescore
  7. 2026-06-25 13:48 UTCEPSS rescore
  8. 2026-06-25 13:48 UTCEPSS rescore
  9. 2026-06-24 14:03 UTCEPSS rescore
  10. 2026-06-24 14:03 UTCEPSS rescore
  11. 2026-06-23 21:31 UTCEPSS rescore
  12. 2026-06-23 21:31 UTCEPSS rescore
  13. 2026-06-22 14:24 UTCEPSS rescore
  14. 2026-06-21 01:58 UTCEPSS rescore
  15. 2026-06-21 01:58 UTCEPSS rescore
  16. 2026-06-19 19:24 UTCEPSS rescore
  17. 2026-06-19 19:24 UTCEPSS rescore
  18. 2026-06-18 17:51 UTCEPSS rescore
  19. 2026-06-18 17:51 UTCEPSS rescore
  20. 2026-06-17 17:51 UTCEPSS rescore
  21. 2026-06-17 17:51 UTCEPSS rescore
  22. 2026-06-17 17:51 UTCEPSS rescore
  23. 2026-06-15 17:46 UTCEPSS rescore
  24. 2026-06-13 22:58 UTCEPSS rescore
  25. 2026-06-13 22:58 UTCEPSS rescore
  26. 2026-06-12 23:10 UTCEPSS rescore
  27. 2026-06-10 22:16 UTCEPSS rescore
  28. 2026-06-10 22:16 UTCEPSS rescore
  29. 2026-06-10 13:20 UTCEPSS rescore
  30. 2026-06-08 14:15 UTCEPSS rescore
  31. 2026-06-08 14:15 UTCEPSS rescore
  32. 2026-06-07 15:23 UTCEPSS rescore
  33. 2026-06-07 15:23 UTCEPSS rescore
  34. 2026-06-05 22:45 UTCEPSS rescore
  35. 2026-06-01 13:50 UTCEPSS rescore
  36. 2026-06-01 13:50 UTCEPSS rescore
  37. 2026-05-29 13:42 UTCEPSS rescore
  38. 2026-05-28 13:43 UTCEPSS rescore
  39. 2026-05-28 13:43 UTCEPSS rescore
  40. 2026-05-26 13:42 UTCEPSS rescore
  41. 2026-05-26 13:42 UTCEPSS rescore
  42. 2026-05-26 07:17 UTCEPSS rescore
  43. 2026-05-26 07:17 UTCEPSS rescore
  44. 2026-05-26 07:17 UTCEPSS rescore
  45. 2026-05-26 06:34 UTCEG score recompute
  46. 2026-05-26 06:34 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/2021/CVE-2021-40856.yaml
    First seen Jan 1, 2021

    Auerswald COMfortel 1400/2600/3600 IP - Authentication Bypass

    Open source ↗

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2021-40856?
CVE-2021-40856 is a high vulnerability published on December 13, 2021. Auerswald COMfortel 1400 IP and 2600 IP before 2.8G devices allow Authentication Bypass via the /about/../ substring.
When was CVE-2021-40856 disclosed?
CVE-2021-40856 was first published in the National Vulnerability Database on December 13, 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-2021-40856 actively exploited?
CVE-2021-40856 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 98.8% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-40856?
CVE-2021-40856 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.
How do I remediate CVE-2021-40856?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-40856, 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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