CVE-2026-59564

CRITICALPre-NVD 9.19.1—
EchelonGraph scoreHIGH confidence

Score 9.1 from GitHub Security Advisory (severity: CRITICAL) published 2026-08-24. a secondary CVSS source baseline 9.1; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this week
9.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 9.1Exploit: None knownExposed: 0

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

An authentication bypass issue exists in communications between affected versions of the Zscaler Client Connector and the Zscaler Client Connector Portal.

CVSS v3
9.1
EG Score
9.1(high)
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
Severity91% × 45%
Exploitation0% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
23%
KEV
Not listed

Published

August 24, 2026

Last Modified

August 28, 2026

Advisory Details (1)

Auto-updated Sep 15, 2026
No patch confirmed yet.
generic
https://help.zscaler.com/zscaler-client-connector/client-connector-app-release-summary-2026

Vendor Advisories for CVE-2026-59564(1)

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 55× in last 7d / 201× 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 201 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-59564?
CVE-2026-59564 is a critical vulnerability published on August 24, 2026. An authentication bypass issue exists in communications between affected versions of the Zscaler Client Connector and the Zscaler Client Connector Portal.
When was CVE-2026-59564 disclosed?
CVE-2026-59564 was first published in the National Vulnerability Database on August 24, 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-2026-59564 actively exploited?
CVE-2026-59564 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 77.2% of all scored CVEs.
What is the CVSS score of CVE-2026-59564?
CVE-2026-59564 has a CVSS v3 base score of 9.1 (NVD).
How do I remediate CVE-2026-59564?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-59564, 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.

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