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Critical, CVSS 9.3

Microsoft Kiota: Path/URL injection into generated Copilot plugin manifest via x-ai-* extensions

CVE-2026-59864GHSA-4jwf-m4wg-8p66

What to do

Vendor fix available. Upgrade each affected package to the fixed version on its release line (microsoft.openapi.kiota 1.32.5, 1.29.1; microsoft.openapi.kiota.builder 1.32.5, 1.29.1), redeploy, then verify what is actually installed.

This page has no inventory attached, so it cannot say whether you are affected. A vendor fix is not proof that your deployment is fixed.

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Affected packages

Sources

Severity and exploitation
Exploitation
No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
CVSS 4.0
9.3 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N · score source
EPSS
  • CVE-2026-59864: 1.33% estimated exploitation activity in the next 30 days; percentile 71.12 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.
Source description

As published by the source; long descriptions are shortened.

Summary kiota plugin add / kiota plugin generate (with -t APIPlugin) emits an attacker-controlled statictemplate.file path from the AI-plugin extensions (x-ai-adaptive-card, x-ai-capabilities) verbatim, with no path validation, into the generated Microsoft 365 Copilot / Teams plugin manifest (<name-apiplugin.json). An attacker-controlled or compromised OpenAPI description can therefore embed a ../ / absolute path into the manifest's responsesemantics.statictemplate.file, yielding a path traversal (CWE-22) / out-of-package file inclusion (CWE-829) that is resolved by the AI host when the generated plugin is deployed. Confirmed on Kiota 1.32.4 (KIOTACONFIGPREVIEW=true, the self-contained linux-x64 release binary). Details Both extension paths write the statictemplate.file reference straight into the manifest without sanitization — PluginsGenerationService.GetResponseSemanticsFromAdaptiveCardExtension mints statictemplate = {"file": <File}, and the x-ai-capabilities path copies the…

Dates and revisions
Published by the source
Last modified by the source
Source last checked
  1. Revision 1 · created ·

    Published from ghsa record GHSA-4jwf-m4wg-8p66

Agent brief

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# Patch Next advisory brief: CVE-2026-59864

Advisory: Microsoft Kiota: Path/URL injection into generated Copilot plugin manifest via x-ai-* extensions
IDs: CVE-2026-59864, GHSA-4jwf-m4wg-8p66
Record: https://patchnext.com/advisories/cve-2026-59864 (revision 1, source checked 26 Oct 2026, 17:05 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Critical (CVSS 9.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: microsoft.openapi.kiota 1.32.5, 1.29.1; microsoft.openapi.kiota.builder 1.32.5, 1.29.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- NuGet microsoft.openapi.kiota: affected >= 1.30.0, < 1.32.5; < 1.29.1; fixed in 1.29.1, 1.32.5
- NuGet microsoft.openapi.kiota.builder: affected >= 1.30.0, < 1.32.5; < 1.29.1; fixed in 1.29.1, 1.32.5

## Suggested inspection (read-only)
- NuGet microsoft.openapi.kiota: check the installed version with your package manager.
- NuGet microsoft.openapi.kiota.builder: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on microsoft.openapi.kiota, microsoft.openapi.kiota.builder.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-4jwf-m4wg-8p66 (GitHub-reviewed advisory GHSA-4jwf-m4wg-8p66 lists affected ranges: NuGet microsoft.openapi.kiota >=1.30.0 =0 =1.30.0 =0 <1.29.1)

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