CVE-2021-35211

CRITICALNVD 9.010.0▲
EchelonGraph scoreHIGH confidence

Score elevated to 10.0 because this CVE is listed on the CISA Known Exploited Vulnerabilities catalog (added 2021-11-03), indicating real-world exploitation has been confirmed by US federal agencies. NVD baseline CVSS 9.0 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
10.0EG
EchelonGraph verdictPatch nowTreat as an emergency — this is being exploited.
  • Actively exploited in the wild (CISA-KEV)
CISA-KEV: ExploitedEPSS PROB: 91%CVSS: 9.0Exploit: cisa kev · ssvc active · kev ransomware · epss top5pct · epss high · public exploitExposed: 0

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

Microsoft discovered a remote code execution (RCE) vulnerability in the SolarWinds Serv-U product utilizing a Remote Memory Escape Vulnerability. If exploited, a threat actor may be able to gain privileged access to the machine hosting Serv-U Only. SolarWinds Serv-U Managed File Transfer and Serv-U Secure FTP for Windows before 15.2.3 HF2 are affected by this vulnerability.

CVSS v3
9.0
EG Score
10.0(high)
EG Risk
85(Attend)
EG Risk 85/100SSVC: Attend

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
Severity100% × 45%
Exploitation100% × 40%
Automatability0% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
91%
EPSS %ILE
100%
KEV
⚠ Exploited

Published

July 14, 2021

Last Modified

October 27, 2025

Advisory Details (3)

Auto-updated Jun 2, 2026
⚠️ Active exploitation confirmed. Patch available. Sources: microsoft, 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-2021-35211
generic🟡 PoC Available

SolarWinds Trust Center Security Advisories | CVE-2021-35211 | SolarWinds

https://www.solarwinds.com/trust-center/security-advisories/cve-2021-35211
microsoft Patch Available

Microsoft discovers threat actor targeting SolarWinds Serv-U software with 0-day exploit | Microsoft Security Blog

Microsoft discovers threat actor targeting SolarWinds Serv-U software with 0-day exploit | Microsoft Security Blog. Patch available via Microsoft Security Update

Affected: Windows 11 apps_nav", "ecn": "FooterNav_Whats_New_Footer_WhatsNew_Windows_11_apps_nav&quot

https://www.microsoft.com/security/blog/2021/07/13/microsoft-discovers-threat-actor-targeting-solarwinds-serv-u-software-with-0-day-exploit

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 49× in last 7d / 214× 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 756 total refreshes for this CVE.

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

Publicly available exploits

(3 references)

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

  • GitHub PoCBishopFox/CVE-2021-35211
    First seen Jan 14, 2022
    Open source ↗
  • GitHub PoCNattiSamson/Serv-U-CVE-2021-35211
    First seen Sep 30, 2021

    Simple Serv-U CVE-2021-35211 PoC

    Open source ↗
  • Nucleijavascript/cves/2021/CVE-2021-35211.yaml
    First seen Jan 1, 2021

    SolarWinds Serv-U FTP - Remote Code Execution

    Open source ↗

Related CVEs(same CWE)

Frequently asked(6)

What is CVE-2021-35211?
CVE-2021-35211 is a critical vulnerability published on July 14, 2021. Microsoft discovered a remote code execution (RCE) vulnerability in the SolarWinds Serv-U product utilizing a Remote Memory Escape Vulnerability. If exploited, a threat actor may be able to gain privileged access to the machine hosting Serv-U Only. SolarWinds Serv-U Managed File Transfer and Serv-U…
When was CVE-2021-35211 disclosed?
CVE-2021-35211 was first published in the National Vulnerability Database on July 14, 2021, with the most recent update on October 27, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-35211 actively exploited?
Yes. CISA added CVE-2021-35211 to the Known Exploited Vulnerabilities catalog on November 3, 2021, affecting SolarWinds Serv-U. KEV listing indicates confirmed exploitation in the wild; this CVE warrants immediate patching attention.
What is the CVSS score of CVE-2021-35211?
CVE-2021-35211 has a CVSS v3 base score of 9.0 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 10.0.
Which products are affected by CVE-2021-35211?
CVE-2021-35211 affects SolarWinds Serv-U. 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-2021-35211?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-35211, 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-2021-35211

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