CVE-2026-6657

HIGHNVD 8.88.8—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.8 under NVD CVSS v3. EPSS exploit probability: 0.2%, top 90% of all CVEs by exploit prediction. GitHub Security Advisory enrichment pending alignment with NVD CVSS.

Triggered by: NVD CVSS baseline
Sources: epss, ghsa, nvd
Elevated
8.8
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 8.8Exploit: NoneExposed: 0

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

A vulnerability in jupyter-server versions 1.12.0 through 2.17.0 allows an attacker to bypass CORS origin validation when the allow_origin_pat configuration is used. The issue arises from the use of re.match() for validating the Origin header, which only anchors at the start of the string. This allows attacker-controlled domains such as trusted.example.com.evil.com to pass validation against patterns intended to match trusted.example.com. The vulnerability affects multiple locations in the codebase, including CORS headers, WebSocket connections, referer validation, and login redirects, potentially enabling phishing attacks, arbitrary code execution, and unauthorized access to sensitive API responses.

CVSS v3
8.8
EG Score
8.8(medium)
EG Risk
56(Track)
EG Risk 56/100SSVC: 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
Severity88% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
9.7%
KEV
Not listed

Published

June 3, 2026

Last Modified

July 21, 2026

Advisory Details (1)

Auto-updated Jun 13, 2026
No patch confirmed yet.
generic

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Vendor Advisories for CVE-2026-6657(1)

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

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
pipjupyter-server—ghsa

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(1 across 1 ecosystem)
PyPI(1)
PackageVulnerable rangeFixed inDependents
jupyter-server1.12.0 ... 2.9.1 (85 versions)——

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 10× in last 7d / 55× 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. 2026-07-23 03:22 UTCEG score recompute▲ 2.70
  2. 2026-07-22 14:08 UTCEPSS rescore
  3. 2026-07-22 14:08 UTCEPSS rescore
  4. 2026-07-21 15:25 UTCEPSS rescore
  5. 2026-07-21 15:25 UTCEPSS rescore
  6. 2026-07-20 17:08 UTCEPSS rescore
  7. 2026-07-19 14:31 UTCEPSS rescore
  8. 2026-07-19 02:29 UTCEPSS rescore
  9. 2026-07-18 10:04 UTCEPSS rescore
  10. 2026-07-16 17:03 UTCEPSS rescore
  11. 2026-07-16 00:38 UTCGHSA enrichment
  12. 2026-07-15 02:00 UTCEPSS rescore
  13. 2026-07-14 03:30 UTCGHSA enrichment
  14. 2026-07-13 22:31 UTCEPSS rescore
  15. 2026-07-13 06:13 UTCEPSS rescore
  16. 2026-07-13 06:13 UTCEPSS rescore
  17. 2026-07-12 05:46 UTCEPSS rescore
  18. 2026-07-11 12:42 UTCGHSA enrichment
  19. 2026-07-11 08:27 UTCEPSS rescore
  20. 2026-07-11 08:27 UTCEPSS rescore
  21. 2026-07-09 19:10 UTCEPSS rescore
  22. 2026-07-09 19:10 UTCEPSS rescore
  23. 2026-07-08 16:26 UTCGHSA enrichment
  24. 2026-07-08 15:16 UTCEPSS rescore
  25. 2026-07-08 15:16 UTCEPSS rescore
Show 70 more
  1. 2026-07-07 13:46 UTCEPSS rescore
  2. 2026-07-07 13:46 UTCEPSS rescore
  3. 2026-07-06 16:27 UTCEPSS rescore
  4. 2026-07-06 16:27 UTCEPSS rescore
  5. 2026-07-06 02:23 UTCEPSS rescore
  6. 2026-07-06 02:23 UTCEPSS rescore
  7. 2026-07-05 02:31 UTCEPSS rescore
  8. 2026-07-05 02:30 UTCEPSS rescore
  9. 2026-07-04 06:31 UTCEPSS rescore
  10. 2026-07-04 06:31 UTCEPSS rescore
  11. 2026-07-03 19:50 UTCGHSA enrichment
  12. 2026-07-02 00:16 UTCGHSA enrichment
  13. 2026-07-01 15:07 UTCEPSS rescore
  14. 2026-06-30 23:22 UTCEPSS rescore
  15. 2026-06-30 22:11 UTCGHSA enrichment
  16. 2026-06-30 20:33 UTCNVD updateCVSS v3 → 8.8 · severity → HIGH
  17. 2026-06-29 14:06 UTCEPSS rescore
  18. 2026-06-29 10:50 UTCGHSA enrichment
  19. 2026-06-28 14:07 UTCEPSS rescore
  20. 2026-06-28 05:54 UTCGHSA enrichment
  21. 2026-06-28 04:56 UTCEPSS rescore
  22. 2026-06-27 03:48 UTCGHSA enrichment
  23. 2026-06-27 03:08 UTCEPSS rescore
  24. 2026-06-26 01:23 UTCGHSA enrichment
  25. 2026-06-25 13:50 UTCEPSS rescore
  26. 2026-06-24 22:22 UTCGHSA enrichment
  27. 2026-06-24 14:05 UTCEPSS rescore
  28. 2026-06-23 21:33 UTCEPSS rescore
  29. 2026-06-23 21:33 UTCEPSS rescore
  30. 2026-06-23 19:07 UTCGHSA enrichment
  31. 2026-06-22 14:25 UTCEPSS rescore
  32. 2026-06-22 14:25 UTCEPSS rescore
  33. 2026-06-21 14:56 UTCEPSS rescore
  34. 2026-06-21 14:56 UTCEPSS rescore
  35. 2026-06-21 01:59 UTCEPSS rescore
  36. 2026-06-21 01:59 UTCEPSS rescore
  37. 2026-06-19 23:52 UTCGHSA enrichment
  38. 2026-06-19 19:26 UTCEPSS rescore
  39. 2026-06-19 19:26 UTCEPSS rescore
  40. 2026-06-18 21:33 UTCGHSA enrichment
  41. 2026-06-17 18:50 UTCGHSA enrichment
  42. 2026-06-17 17:53 UTCEPSS rescore
  43. 2026-06-16 17:53 UTCEPSS rescore
  44. 2026-06-16 16:40 UTCGHSA enrichment
  45. 2026-06-15 17:49 UTCEPSS rescore
  46. 2026-06-15 17:49 UTCEPSS rescore
  47. 2026-06-15 14:36 UTCGHSA enrichment
  48. 2026-06-14 23:18 UTCEPSS rescore
  49. 2026-06-14 12:32 UTCGHSA enrichment
  50. 2026-06-13 23:00 UTCEPSS rescore
  51. 2026-06-13 10:27 UTCGHSA enrichment
  52. 2026-06-12 23:12 UTCEPSS rescore
  53. 2026-06-12 23:12 UTCEPSS rescore
  54. 2026-06-12 08:21 UTCGHSA enrichment
  55. 2026-06-11 14:00 UTCEPSS rescore
  56. 2026-06-11 06:17 UTCGHSA enrichment
  57. 2026-06-10 22:19 UTCEPSS rescore
  58. 2026-06-10 13:22 UTCEPSS rescore
  59. 2026-06-10 04:13 UTCGHSA enrichment
  60. 2026-06-09 02:10 UTCGHSA enrichment
  61. 2026-06-08 14:17 UTCEPSS rescore
  62. 2026-06-08 00:05 UTCGHSA enrichment
  63. 2026-06-07 15:25 UTCEPSS rescore
  64. 2026-06-06 22:02 UTCGHSA enrichment
  65. 2026-06-06 13:47 UTCEPSS rescore
  66. 2026-06-05 22:47 UTCEPSS rescore
  67. 2026-06-05 19:58 UTCGHSA enrichment
  68. 2026-06-05 06:10 UTCEPSS rescore
  69. 2026-06-04 17:54 UTCGHSA enrichment
  70. 2026-06-03 15:50 UTCEG score recompute

Frequently asked(5)

What is CVE-2026-6657?
CVE-2026-6657 is a high vulnerability published on June 3, 2026. A vulnerability in jupyter-server versions 1.12.0 through 2.17.0 allows an attacker to bypass CORS origin validation when the alloworiginpat configuration is used. The issue arises from the use of re.match() for validating the Origin header, which only anchors at the start of the string. This…
When was CVE-2026-6657 disclosed?
CVE-2026-6657 was first published in the National Vulnerability Database on June 3, 2026, with the most recent update on July 21, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-6657 actively exploited?
CVE-2026-6657 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 9.7% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-6657?
CVE-2026-6657 has a CVSS v3 base score of 8.8 (NVD).
How do I remediate CVE-2026-6657?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-6657, 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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