CVE-2026-42897

HIGHPre-NVD 8.19.0▲
EchelonGraph scoreHIGH confidence

Score elevated to 9.0 because this CVE is listed on the CISA Known Exploited Vulnerabilities catalog (added 2026-05-15), indicating real-world exploitation has been confirmed by US federal agencies. the CNA's CVSS baseline 8.1 retained for reference (NVD's own analysis pending). Confidence: HIGH.

Triggered by: CISA KEV (actively exploited)
Sources: cisa_kev, cna:microsoft, epss, ghsa
Trending — 5 sources updated this weekExploited in the wild
8.1
EchelonGraph verdictPatch nowTreat as an emergency — this is being exploited.
  • Actively exploited in the wild (CISA-KEV)
CISA-KEV: ExploitedEPSS: 6%CVSS: 8.1Exploit: NoneExposed: 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 Exchange Server allows an unauthorized attacker to perform spoofing over a network.

CVSS v3
8.1
EG Score
9.0(high)
EPSS
92.1%
KEV
⚠ Exploited

Published

May 14, 2026

Last Modified

June 19, 2026

Advisory Details (1)

Auto-updated May 14, 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-2026-42897

Vendor Advisories for CVE-2026-42897(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 0× in last 7d / 0× 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.

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

Publicly available exploits

(1 reference)

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

  • GitHub PoCatiilla/CVE-2026-42897
    First seen May 15, 2026

    CVE-2026-42897 - Exchange Health Checker blind spot: outbound IIS URL Rewrite rules silently ignored, making EOMT mitigations invisible in diagnostic reports.

    Open source ↗

Frequently asked(6)

What is CVE-2026-42897?
CVE-2026-42897 is a high vulnerability published on May 14, 2026. Improper neutralization of input during web page generation ('cross-site scripting') in Microsoft Exchange Server allows an unauthorized attacker to perform spoofing over a network.
When was CVE-2026-42897 disclosed?
CVE-2026-42897 was first published in the National Vulnerability Database on May 14, 2026, with the most recent update on June 19, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-42897 actively exploited?
Yes. CISA added CVE-2026-42897 to the Known Exploited Vulnerabilities catalog on May 15, 2026, affecting Microsoft Microsoft. KEV listing indicates confirmed exploitation in the wild; this CVE warrants immediate patching attention.
What is the CVSS score of CVE-2026-42897?
CVE-2026-42897 has a CVSS v4.0 base score of 8.1 (CNA self-assessment; NVD's own analysis pending). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 9.0.
Which products are affected by CVE-2026-42897?
CVE-2026-42897 affects Microsoft Microsoft. 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-2026-42897?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-42897, 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-2026-42897

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