---
title: "CVE-2026-59864: Microsoft Kiota: Path/URL injection into generated Copilot plugin manifest via x-ai-* extensions"
url: https://erroneo.us/security/cve/CVE-2026-59864/
description: "CVE-2026-59864 (Microsoft.OpenApi.Kiota (NuGet)): Kiota is an OpenAPI based HTTP Client code generator. Prior to 1.29.1 and 1.32.5, kiota plugin add and…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-07-16
date_modified: 2026-08-17
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-59864"
kev: false
cvss: 9.3
epss: 0.01331
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-59864: Microsoft Kiota: Path/URL injection into generated Copilot plugin manifest via x-ai-* extensions

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 1.3% , percentile 71: FIRST’s model estimates a 1.3% chance of exploitation activity in the next 30 days, higher than 71% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes Microsoft.OpenApi.Kiota (NuGet) >= 1.30.0, < 1.32.5, fixed in 1.32.5 ; Microsoft.OpenApi.Kiota.Builder (NuGet) >= 1.30.0, < 1.32.5, fixed in 1.32.5 ; Microsoft.OpenApi.Kiota (NuGet) < 1.29.1, fixed in 1.29.1 ; Microsoft.OpenApi.Kiota.Builder (NuGet) < 1.29.1, fixed in 1.29.1 . Check your lockfile, including transitive dependencies.

## What it is

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 manifests without path validation, allowing ../, absolute, rooted, UNC, Windows drive, or URI paths in responsesemantics.statictemplate.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.

## Affected packages

- NuGet `Microsoft.OpenApi.Kiota` >= 1.30.0, < 1.32.5 → fixed: 1.32.5
- NuGet `Microsoft.OpenApi.Kiota.Builder` >= 1.30.0, < 1.32.5 → fixed: 1.32.5
- NuGet `Microsoft.OpenApi.Kiota` < 1.29.1 → fixed: 1.29.1
- NuGet `Microsoft.OpenApi.Kiota.Builder` < 1.29.1 → fixed: 1.29.1

## Affected products (CVE record)

- microsoft kiota: >= 1.30.0, < 1.31.1, < 1.29.1

## Severity

- GitHub_M 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`
- GitHub 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`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none , automatable yes , technical impact total .
- FIRST EPSS (model of 2026-10-21): 1.33% probability of exploitation activity in the next 30 days; percentile 71.

## Sources

- [GitHub Advisory GHSA-4jwf-m4wg-8p66](https://github.com/advisories/GHSA-4jwf-m4wg-8p66)
- [CVE.org record CVE-2026-59864](https://www.cve.org/CVERecord?id=CVE-2026-59864)
- [NVD entry CVE-2026-59864](https://nvd.nist.gov/vuln/detail/CVE-2026-59864)
- [github.com](https://github.com/microsoft/kiota/security/advisories/GHSA-4jwf-m4wg-8p66)
- [github.com](https://github.com/microsoft/kiota/pull/7892)
- [github.com](https://github.com/microsoft/kiota/commit/9a185994a4e549b7bba3cc2beffb9736aa902e79)
- [github.com](https://github.com/microsoft/kiota/releases/tag/v1.32.5)

---
Source page: https://erroneo.us/security/cve/CVE-2026-59864/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt