CVE-2021-35394

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 2021-12-10), 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: 100%CVSS: 9.8Exploit: NoneExposed: 0

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

Realtek Jungle SDK version v2.x up to v3.4.14B provides a diagnostic tool called 'MP Daemon' that is usually compiled as 'UDPServer' binary. The binary is affected by multiple memory corruption vulnerabilities and an arbitrary command injection vulnerability that can be exploited by remote unauthenticated attackers.

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
100.0%
KEV
⚠ Exploited

Published

August 16, 2021

Last Modified

November 7, 2025

Advisory Details (3)

Auto-updated Jun 1, 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-2021-35394
generic
https://www.securityfocus.com/archive/1/534765
generic

Oops!

https://www.realtek.com/en/cu-1-en/cu-1-taiwan-en

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 39× in last 7d / 201× 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 384 total refreshes for this CVE.

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

  • Nucleijavascript/cves/2021/CVE-2021-35394.yaml
    First seen Jan 1, 2021

    RealTek AP Router SDK - Arbitrary Command Injection

    Open source ↗

Related CVEs(same CWE)

Frequently asked(6)

What is CVE-2021-35394?
CVE-2021-35394 is a critical vulnerability published on August 16, 2021. Realtek Jungle SDK version v2.x up to v3.4.14B provides a diagnostic tool called 'MP Daemon' that is usually compiled as 'UDPServer' binary. The binary is affected by multiple memory corruption vulnerabilities and an arbitrary command injection vulnerability that can be exploited by remote…
When was CVE-2021-35394 disclosed?
CVE-2021-35394 was first published in the National Vulnerability Database on August 16, 2021, 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-2021-35394 actively exploited?
Yes. CISA added CVE-2021-35394 to the Known Exploited Vulnerabilities catalog on December 10, 2021, affecting Realtek Jungle Software Development Kit (SDK). KEV listing indicates confirmed exploitation in the wild; this CVE warrants immediate patching attention.
What is the CVSS score of CVE-2021-35394?
CVE-2021-35394 has a CVSS v3 base score of 9.8 (NVD).
Which products are affected by CVE-2021-35394?
CVE-2021-35394 affects Realtek Jungle Software Development Kit (SDK). 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-2021-35394?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-35394, 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-2021-35394

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