CVE-2026-55021

HIGHPre-NVD 7.37.3—
EchelonGraph scoreMEDIUM confidence

Score 7.3 from GitHub Security Advisory (severity: HIGH) published 2026-07-14. the CNA's CVSS baseline 7.3; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cna:microsoft, epss, ghsa
Trending — 4 sources updated this week
7.3EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 7.3Exploit: None knownExposed: 0

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

Improper neutralization of input during web page generation ('cross-site scripting') in Microsoft Office SharePoint allows an authorized attacker to perform spoofing over a network.

CVSS v3
7.3
EG Score
7.3(medium)
EG Risk
33(Track)
EG Risk 33/100SSVC: 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
Severity73% × 45%
Exploitation1% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
58%
KEV
Not listed

Published

July 14, 2026

Last Modified

August 28, 2026

Advisory Details (1)

Auto-updated Jul 15, 2026
Patch available. Sources: microsoft.
microsoft Patch Available

Security Update Guide - Microsoft Security Response Center

Security Update Guide - Microsoft Security Response Center. Patch available via Microsoft Security Update

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55021

Vendor Advisories for CVE-2026-55021(2)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 34× in last 7d / 173× 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 244 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-55021?
CVE-2026-55021 is a high vulnerability published on July 14, 2026. Improper neutralization of input during web page generation ('cross-site scripting') in Microsoft Office SharePoint allows an authorized attacker to perform spoofing over a network.
When was CVE-2026-55021 disclosed?
CVE-2026-55021 was first published in the National Vulnerability Database on July 14, 2026, with the most recent update on August 28, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-55021 actively exploited?
CVE-2026-55021 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 41.9% of all scored CVEs.
What is the CVSS score of CVE-2026-55021?
CVE-2026-55021 has a CVSS v4.0 base score of 7.3 (CNA self-assessment; NVD's own analysis pending).
How do I remediate CVE-2026-55021?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-55021, 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

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