CVE-2021-20038

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 2022-01-28), 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 — 3 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.

A Stack-based buffer overflow vulnerability in SMA100 Apache httpd server's mod_cgi module environment variables allows a remote unauthenticated attacker to potentially execute code as a 'nobody' user in the appliance. This vulnerability affected SMA 200, 210, 400, 410 and 500v appliances firmware 10.2.0.8-37sv, 10.2.1.1-19sv, 10.2.1.2-24sv and earlier versions.

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

December 8, 2021

Last Modified

October 31, 2025

Advisory Details (4)

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-2021-20038
generic🔴 Active Exploitation

CVE-2021-20038..42: SonicWall SMA 100 Multiple Vulnerabilities (FIXED) | Rapid7 Blog

https://www.rapid7.com/blog/post/2022/01/11/cve-2021-20038-42-sonicwall-sma-100-multiple-vulnerabilities-fixed-2/
generic

Security Advisory

https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0026
generic

GitHub - jbaines-r7/badblood: SonicWall SMA-100 Unauth RCE Exploit (CVE-2021-20038) · GitHub

https://github.com/jbaines-r7/badblood

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 40× in last 7d / 186× 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 346 total refreshes for this CVE.

  1. 2026-07-23 01:56 UTCEG score recompute
  2. 2026-07-22 21:42 UTCEG score recompute
  3. 2026-07-22 21:42 UTCGHSA enrichment
  4. 2026-07-22 19:40 UTCCISA KEV update
  5. 2026-07-22 17:32 UTCGHSA enrichment
  6. 2026-07-22 13:28 UTCGHSA enrichment
  7. 2026-07-22 09:24 UTCGHSA enrichment
  8. 2026-07-22 05:20 UTCGHSA enrichment
  9. 2026-07-22 01:16 UTCGHSA enrichment
  10. 2026-07-21 21:12 UTCGHSA enrichment
  11. 2026-07-21 17:05 UTCGHSA enrichment
  12. 2026-07-21 14:37 UTCCISA KEV update
  13. 2026-07-21 13:01 UTCGHSA enrichment
  14. 2026-07-21 08:58 UTCGHSA enrichment
  15. 2026-07-21 04:54 UTCGHSA enrichment
  16. 2026-07-21 00:49 UTCGHSA enrichment
  17. 2026-07-20 20:45 UTCGHSA enrichment
  18. 2026-07-20 16:41 UTCGHSA enrichment
  19. 2026-07-20 12:37 UTCGHSA enrichment
  20. 2026-07-20 08:33 UTCGHSA enrichment
  21. 2026-07-20 04:30 UTCGHSA enrichment
  22. 2026-07-19 20:20 UTCGHSA enrichment
  23. 2026-07-19 16:14 UTCGHSA enrichment
  24. 2026-07-19 12:00 UTCGHSA enrichment
  25. 2026-07-19 07:57 UTCGHSA enrichment
Show 75 more
  1. 2026-07-19 03:52 UTCGHSA enrichment
  2. 2026-07-18 23:48 UTCGHSA enrichment
  3. 2026-07-18 19:44 UTCGHSA enrichment
  4. 2026-07-18 15:40 UTCGHSA enrichment
  5. 2026-07-18 11:36 UTCGHSA enrichment
  6. 2026-07-18 07:30 UTCGHSA enrichment
  7. 2026-07-18 03:26 UTCGHSA enrichment
  8. 2026-07-17 23:22 UTCGHSA enrichment
  9. 2026-07-17 19:18 UTCGHSA enrichment
  10. 2026-07-17 15:14 UTCGHSA enrichment
  11. 2026-07-17 11:10 UTCGHSA enrichment
  12. 2026-07-17 07:06 UTCEG score recompute
  13. 2026-07-17 07:06 UTCGHSA enrichment
  14. 2026-07-17 03:02 UTCGHSA enrichment
  15. 2026-07-16 22:56 UTCGHSA enrichment
  16. 2026-07-16 18:52 UTCGHSA enrichment
  17. 2026-07-16 17:04 UTCCISA KEV update
  18. 2026-07-16 14:47 UTCGHSA enrichment
  19. 2026-07-16 10:43 UTCGHSA enrichment
  20. 2026-07-16 06:39 UTCGHSA enrichment
  21. 2026-07-16 02:35 UTCGHSA enrichment
  22. 2026-07-15 22:31 UTCGHSA enrichment
  23. 2026-07-15 18:27 UTCGHSA enrichment
  24. 2026-07-15 16:49 UTCCISA KEV update
  25. 2026-07-15 15:04 UTCCISA KEV update
  26. 2026-07-15 14:22 UTCGHSA enrichment
  27. 2026-07-15 10:17 UTCGHSA enrichment
  28. 2026-07-15 06:12 UTCGHSA enrichment
  29. 2026-07-15 02:09 UTCGHSA enrichment
  30. 2026-07-14 22:03 UTCGHSA enrichment
  31. 2026-07-14 18:05 UTCCISA KEV update
  32. 2026-07-14 17:58 UTCGHSA enrichment
  33. 2026-07-14 13:53 UTCGHSA enrichment
  34. 2026-07-14 09:49 UTCGHSA enrichment
  35. 2026-07-14 05:44 UTCGHSA enrichment
  36. 2026-07-14 01:40 UTCGHSA enrichment
  37. 2026-07-13 21:36 UTCGHSA enrichment
  38. 2026-07-13 17:32 UTCGHSA enrichment
  39. 2026-07-13 17:07 UTCCISA KEV update
  40. 2026-07-13 13:28 UTCGHSA enrichment
  41. 2026-07-13 09:24 UTCGHSA enrichment
  42. 2026-07-13 05:20 UTCGHSA enrichment
  43. 2026-07-13 01:16 UTCGHSA enrichment
  44. 2026-07-12 21:11 UTCGHSA enrichment
  45. 2026-07-12 17:05 UTCGHSA enrichment
  46. 2026-07-12 13:01 UTCGHSA enrichment
  47. 2026-07-12 08:57 UTCGHSA enrichment
  48. 2026-07-12 04:53 UTCGHSA enrichment
  49. 2026-07-12 00:49 UTCGHSA enrichment
  50. 2026-07-11 20:45 UTCGHSA enrichment
  51. 2026-07-11 16:41 UTCGHSA enrichment
  52. 2026-07-11 12:37 UTCGHSA enrichment
  53. 2026-07-11 08:33 UTCGHSA enrichment
  54. 2026-07-11 04:29 UTCGHSA enrichment
  55. 2026-07-11 00:25 UTCGHSA enrichment
  56. 2026-07-10 20:21 UTCGHSA enrichment
  57. 2026-07-10 17:52 UTCCISA KEV update
  58. 2026-07-10 16:17 UTCGHSA enrichment
  59. 2026-07-10 12:13 UTCGHSA enrichment
  60. 2026-07-10 08:09 UTCGHSA enrichment
  61. 2026-07-10 04:04 UTCGHSA enrichment
  62. 2026-07-10 00:00 UTCGHSA enrichment
  63. 2026-07-09 19:56 UTCGHSA enrichment
  64. 2026-07-09 19:07 UTCEPSS rescore
  65. 2026-07-09 15:52 UTCGHSA enrichment
  66. 2026-07-09 11:47 UTCGHSA enrichment
  67. 2026-07-09 07:42 UTCGHSA enrichment
  68. 2026-07-09 03:38 UTCGHSA enrichment
  69. 2026-07-08 23:34 UTCGHSA enrichment
  70. 2026-07-08 19:30 UTCGHSA enrichment
  71. 2026-07-08 15:25 UTCGHSA enrichment
  72. 2026-07-08 11:20 UTCGHSA enrichment
  73. 2026-07-08 07:16 UTCGHSA enrichment
  74. 2026-07-08 03:12 UTCGHSA enrichment
  75. 2026-07-07 23:08 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-2021-20038.yaml
    First seen Jan 1, 2021

    SonicWall SMA100 Stack - Buffer Overflow/Remote Code Execution

    Open source ↗

Related CVEs(same CWE)

Frequently asked(6)

What is CVE-2021-20038?
CVE-2021-20038 is a critical vulnerability published on December 8, 2021. A Stack-based buffer overflow vulnerability in SMA100 Apache httpd server's mod_cgi module environment variables allows a remote unauthenticated attacker to potentially execute code as a 'nobody' user in the appliance. This vulnerability affected SMA 200, 210, 400, 410 and 500v appliances firmware…
When was CVE-2021-20038 disclosed?
CVE-2021-20038 was first published in the National Vulnerability Database on December 8, 2021, with the most recent update on October 31, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-20038 actively exploited?
Yes. CISA added CVE-2021-20038 to the Known Exploited Vulnerabilities catalog on January 28, 2022, affecting SonicWall SMA 100 Appliances. KEV listing indicates confirmed exploitation in the wild; this CVE warrants immediate patching attention.
What is the CVSS score of CVE-2021-20038?
CVE-2021-20038 has a CVSS v3 base score of 9.8 (NVD).
Which products are affected by CVE-2021-20038?
CVE-2021-20038 affects SonicWall SMA 100 Appliances. 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-2021-20038?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-20038, 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-2021-20038

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