CVE-2026-6643

CRITICALNVD 9.99.9—
EchelonGraph scoreMEDIUM confidence

Score 9.9 from GitHub Security Advisory (severity: HIGH) published 2026-04-20. NVD baseline CVSS 9.9; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
9.9EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 9.9Exploit: None knownExposed: 0

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

A stack-based buffer overflow vulnerability was found in the VPN Clients on the ADM. The issue stems from the use of unbounded sscanf() and passing user-controlled data directly to printf(). Due to the lack of PIE and Stack Canary protections, an authenticated remote attacker can exploit these to execute arbitrary code as the web server user. Affected products and versions include: from ADM 4.1.0 through ADM 4.3.3.RR42 as well as from ADM 5.0.0 through ADM 5.1.2.REO1.

CVSS v3
9.9
EG Score
9.9(medium)
EG Risk
45(Track)
EG Risk 45/100SSVC: 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
Severity99% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
38%
KEV
Not listed

Published

April 20, 2026

Last Modified

April 22, 2026

Advisory Details (1)

Auto-updated Jul 27, 2026
No patch confirmed yet.
generic

AS-2026-005: VPN Clients | ASUSTOR NAS

https://www.asustor.com/security/security_advisory_detail?id=54

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 12× in last 7d / 43× 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 142 total refreshes for this CVE.

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

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Frequently asked(5)

What is CVE-2026-6643?
CVE-2026-6643 is a critical vulnerability published on April 20, 2026. A stack-based buffer overflow vulnerability was found in the VPN Clients on the ADM. The issue stems from the use of unbounded sscanf() and passing user-controlled data directly to printf(). Due to the lack of PIE and Stack Canary protections, an authenticated remote attacker can exploit these to…
When was CVE-2026-6643 disclosed?
CVE-2026-6643 was first published in the National Vulnerability Database on April 20, 2026, with the most recent update on April 22, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-6643 actively exploited?
CVE-2026-6643 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 62.1% of all scored CVEs.
What is the CVSS score of CVE-2026-6643?
CVE-2026-6643 has a CVSS v3 base score of 9.9 (NVD).
How do I remediate CVE-2026-6643?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-6643, 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.

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