CVE-2021-42237

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 2022-03-25), 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
9.8EG
EchelonGraph verdictPatch nowTreat as an emergency — this is being exploited.
  • Actively exploited in the wild (CISA-KEV)
CISA-KEV: ExploitedEPSS PROB: 98%CVSS: 9.8Exploit: cisa kev · ssvc active · kev ransomware · Metasploit · 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.

Sitecore XP 7.5 Initial Release to Sitecore XP 8.2 Update-7 is vulnerable to an insecure deserialization attack where it is possible to achieve remote command execution on the machine. No authentication or special configuration is required to exploit this vulnerability.

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 PROB
98%
EPSS %ILE
100%
KEV
⚠ Exploited

Published

November 5, 2021

Last Modified

July 9, 2026

Advisory Details (5)

Auto-updated Sep 5, 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-2021-42237
generic

%kb_name - %short_descr - Knowledge Portal

https://support.sitecore.com/kb?id=kb_article_view&sysparm_article=KB1000776
generic

Sitecore Experience Platform Pre-Auth RCE - CVE-2021-42237

https://blog.assetnote.io/2021/11/02/sitecore-rce/
generic

Locked Out | Packet Storm

http://packetstormsecurity.com/files/164988/Sitecore-Experience-Platform-XP-Remote-Code-Execution.html
generic

AI-powered digital experiences that win | Sitecore

http://sitecore.com

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 45× in last 7d / 198× 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 625 total refreshes for this CVE.

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

Publicly available exploits

(3 references)

Working exploit code is in the public domain (1 Metasploit module) (1 GitHub PoC). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • GitHub PoCItsIgnacioPortal/CVE-2021-42237
    First seen Jan 16, 2022

    An exploit/PoC for CVE-2021-42237

    Open source ↗
  • Metasploitexploit/windows/http/sitecore_xp_cve_2021_42237✓ verified
    First seen Nov 2, 2021

    Sitecore Experience Platform (XP) PreAuth Deserialization RCE

    Open source ↗
  • Nucleihttp/cves/2021/CVE-2021-42237.yaml
    First seen Jan 1, 2021

    Sitecore Experience Platform Pre-Auth RCE

    Open source ↗

Frequently asked(6)

What is CVE-2021-42237?
CVE-2021-42237 is a critical vulnerability published on November 5, 2021. Sitecore XP 7.5 Initial Release to Sitecore XP 8.2 Update-7 is vulnerable to an insecure deserialization attack where it is possible to achieve remote command execution on the machine. No authentication or special configuration is required to exploit this vulnerability.
When was CVE-2021-42237 disclosed?
CVE-2021-42237 was first published in the National Vulnerability Database on November 5, 2021, with the most recent update on July 9, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-42237 actively exploited?
Yes. CISA added CVE-2021-42237 to the Known Exploited Vulnerabilities catalog on March 25, 2022, affecting Sitecore XP. KEV listing indicates confirmed exploitation in the wild; this CVE warrants immediate patching attention.
What is the CVSS score of CVE-2021-42237?
CVE-2021-42237 has a CVSS v3 base score of 9.8 (NVD).
Which products are affected by CVE-2021-42237?
CVE-2021-42237 affects Sitecore XP. 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-2021-42237?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-42237, 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-2021-42237

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