CVE-2026-59864

CRITICALPre-NVD 9.39.3—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 1.3%, top 31% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
9.3EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 9.3Exploit: None knownExposed: 0

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

Kiota is an OpenAPI based HTTP Client code generator. Prior to 1.29.1 and 1.32.5, kiota plugin add and kiota plugin generate (with -t APIPlugin) emitted attacker-controlled static_template.file values from x-ai-adaptive-card and x-ai-capabilities into generated Microsoft 365 Copilot and Teams plugin manifests without path validation, allowing ../, absolute, rooted, UNC, Windows drive, or URI paths in response_semantics.static_template.file to cause path traversal or out-of-package file inclusion when the generated plugin was deployed. This issue is fixed in version 1.29.1 and 1.32.5.

CVSS v3
9.3
EG Score
9.3(medium)
EG Risk
57(Track)
EG Risk 57/100SSVC: 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
Severity93% × 45%
Exploitation1% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
69%
KEV
Not listed

Published

July 16, 2026

Last Modified

August 17, 2026

Advisory Details (4)

Auto-updated Sep 3, 2026
Patch available. Sources: github_release, github, github_commit, github_pr.
github Patch Available

Path/URL injection into generated Copilot plugin manifest via x-ai-* extensions (Microsoft Kiota) · Advisory · microsoft/kiota · GitHub

https://github.com/microsoft/kiota/security/advisories/GHSA-4jwf-m4wg-8p66
github_release Patch Available

v1.32.5

Patch available: microsoft/kiota v1.32.5

https://github.com/microsoft/kiota/releases/tag/v1.32.5
github_pr

fix: reject unsafe static_template.file references in plugin manifest generation

Fix merged in microsoft/kiota PR #7892 on 2026-07-03 — awaiting tagged release

https://github.com/microsoft/kiota/pull/7892
github_commit

commit 9a185994a4e5 (microsoft/kiota)

Fix landed in microsoft/kiota commit 9a185994a4e5 — awaiting tagged release

https://github.com/microsoft/kiota/commit/9a185994a4e549b7bba3cc2beffb9736aa902e79

Vendor Advisories for CVE-2026-59864(1)

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

Affected Packages

(2 across 1 ecosystem)
NuGet(2)
PackageVulnerable rangeFixed inDependents
Microsoft.OpenApi.Kiota0.1.0-preview ... 1.9.1 (66 versions)1.29.1—
Microsoft.OpenApi.Kiota.Builder0.2.0-preview ... 1.9.1 (46 versions)1.29.1—

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 8× in last 7d / 43× 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. 2026-09-11 14:53 UTCEPSS rescore
  2. 2026-09-10 09:35 UTCEPSS rescore
  3. 2026-09-08 22:01 UTCEPSS rescore
  4. 2026-09-08 00:30 UTCEG score recompute
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  10. 2026-09-02 14:12 UTCEPSS rescore
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  13. 2026-08-30 19:53 UTCEG score recompute
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  24. 2026-08-24 19:21 UTCEG score recompute
  25. 2026-08-24 12:16 UTCEG score recompute
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  1. 2026-08-23 04:15 UTCEG score recompute
  2. 2026-08-23 00:19 UTCEPSS rescore
  3. 2026-08-21 23:52 UTCEG score recompute
  4. 2026-08-21 23:49 UTCEPSS rescore
  5. 2026-08-21 00:07 UTCEG score recompute
  6. 2026-08-20 22:55 UTCEPSS rescore
  7. 2026-08-19 23:55 UTCEG score recompute
  8. 2026-08-19 17:04 UTCEPSS rescore
  9. 2026-08-18 19:56 UTCEG score recompute
  10. 2026-08-18 13:48 UTCEPSS rescore
  11. 2026-08-16 16:25 UTCEG score recompute
  12. 2026-08-16 14:56 UTCEPSS rescore
  13. 2026-08-16 04:35 UTCEG score recompute
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  15. 2026-08-15 04:47 UTCEG score recompute
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  18. 2026-08-13 22:00 UTCEPSS rescore
  19. 2026-08-12 17:36 UTCEG score recompute
  20. 2026-08-12 13:51 UTCEPSS rescore
  21. 2026-08-11 13:49 UTCEG score recompute
  22. 2026-08-11 01:59 UTCEG score recompute
  23. 2026-08-11 00:00 UTCEPSS rescore
  24. 2026-08-09 14:06 UTCEG score recompute
  25. 2026-08-09 13:46 UTCEPSS rescore
  26. 2026-08-08 18:22 UTCEG score recompute
  27. 2026-08-08 16:37 UTCEPSS rescore
  28. 2026-08-07 18:42 UTCEG score recompute
  29. 2026-08-06 14:41 UTCEG score recompute
  30. 2026-08-06 13:47 UTCEPSS rescore
  31. 2026-08-05 22:54 UTCEG score recompute
  32. 2026-08-05 19:17 UTCEPSS rescore
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  34. 2026-08-04 15:10 UTCEPSS rescore
  35. 2026-08-04 14:01 UTCEG score recompute
  36. 2026-08-04 10:39 UTCEPSS rescore
  37. 2026-08-03 13:48 UTCEG score recompute
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  39. 2026-08-02 05:20 UTCEG score recompute
  40. 2026-08-02 02:27 UTCEPSS rescore
  41. 2026-08-01 05:38 UTCEG score recompute
  42. 2026-08-01 04:16 UTCEPSS rescore
  43. 2026-07-30 17:08 UTCEG score recompute
  44. 2026-07-30 16:28 UTCEPSS rescore
  45. 2026-07-30 12:44 UTCEG score recompute
  46. 2026-07-30 04:48 UTCEG score recompute
  47. 2026-07-30 01:30 UTCEPSS rescore
  48. 2026-07-30 01:30 UTCEPSS rescore
  49. 2026-07-28 17:09 UTCEG score recompute
  50. 2026-07-28 15:37 UTCEPSS rescore
  51. 2026-07-26 15:23 UTCEG score recompute
  52. 2026-07-26 14:54 UTCEPSS rescore
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  54. 2026-07-26 11:25 UTCEG score recompute
  55. 2026-07-25 14:18 UTCEPSS rescore
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  57. 2026-07-24 14:18 UTCEPSS rescore
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  59. 2026-07-23 14:18 UTCEPSS rescore
  60. 2026-07-23 14:18 UTCEPSS rescore
  61. 2026-07-23 03:21 UTCEG score recompute
  62. 2026-07-22 14:08 UTCEPSS rescore
  63. 2026-07-22 14:08 UTCEPSS rescore
  64. 2026-07-21 15:25 UTCEPSS rescore
  65. 2026-07-21 15:25 UTCEPSS rescore
  66. 2026-07-20 17:08 UTCEPSS rescore
  67. 2026-07-19 02:29 UTCEPSS rescore
  68. 2026-07-18 10:04 UTCEPSS rescore
  69. 2026-07-16 15:24 UTCEG score recompute
  70. 2026-07-16 15:23 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-59864?
CVE-2026-59864 is a critical vulnerability published on July 16, 2026. Kiota is an OpenAPI based HTTP Client code generator. Prior to 1.29.1 and 1.32.5, kiota plugin add and kiota plugin generate (with -t APIPlugin) emitted attacker-controlled statictemplate.file values from x-ai-adaptive-card and x-ai-capabilities into generated Microsoft 365 Copilot and Teams plugin…
When was CVE-2026-59864 disclosed?
CVE-2026-59864 was first published in the National Vulnerability Database on July 16, 2026, with the most recent update on August 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-59864 actively exploited?
CVE-2026-59864 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 30.6% of all scored CVEs.
What is the CVSS score of CVE-2026-59864?
CVE-2026-59864 has a CVSS v3 base score of 9.3 (NVD).
How do I remediate CVE-2026-59864?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-59864, 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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