# CVE-2026-73851: Kiota: Path traversal in generated plugin manifest static_template.file reference (percent-encoding bypass)

> Attackers can manipulate OpenAPI descriptions to cause Kiota to generate manifests that disclose files outside the intended package boundary.

- **Severity:** Medium 6.1 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:H/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 17 Aug 2026
- **Updated:** 17 Aug 2026
- **Also known as:** GHSA-p5rm-jg5c-8c77

## What is CVE-2026-73851?

CVE-2026-73851 is a medium-severity path traversal vulnerability in microsoft kiota, published on 17 Aug 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

Kiota is an OpenAPI based HTTP Client code generator. Prior to 1.29.1 and 1.34.0, an attacker who controls or tampers with the OpenAPI description consumed by Kiota can supply a file reference that resolves outside the manifest package (e.g. ../../../../etc/passwd, an absolute path, or a file:// / http(s):// URI). When the generated manifest is deployed and consumed by an AI host, this can lead to inclusion or disclosure of files outside the intended package boundary. This vulnerability is fixed in 1.29.1 and 1.34.0.

Weakness: CWE-829 (Inclusion of Functionality from Untrusted Control Sphere), CWE-22 (Improper Limitation of a Pathname to a Restricted Directory)

## Which versions are affected by CVE-2026-73851?

4 open source packages ship an affected version, including Microsoft.OpenApi.Kiota.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `Microsoft.OpenApi.Kiota` | NuGet | All versions | 1.29.1 |
| `Microsoft.OpenApi.Kiota` | NuGet | All versions | 1.29.1 |
| `Microsoft.OpenApi.Kiota` | NuGet | From 1.30.0 | 1.34.0 |
| `Microsoft.OpenApi.Kiota` | NuGet | From 1.30.0 | 1.34.0 |

## How do I fix CVE-2026-73851?

Upgrade Microsoft.OpenApi.Kiota to a fixed version for your release line: 1.29.1 or 1.34.0.

## Is CVE-2026-73851 being exploited?

There is no known exploitation of CVE-2026-73851 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-73851 and fix it if it is affected.

What it is: CVE-2026-73851 is a medium-severity path traversal vulnerability in microsoft kiota, published on 17 Aug 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-73851 in the wild and no public exploit code.

Affected packages and fixed versions:
- Microsoft.OpenApi.Kiota (NuGet): affected all versions; fixed in 1.29.1
- Microsoft.OpenApi.Kiota (NuGet): affected all versions; fixed in 1.29.1
- Microsoft.OpenApi.Kiota (NuGet): affected from 1.30.0; fixed in 1.34.0
- Microsoft.OpenApi.Kiota (NuGet): affected from 1.30.0; fixed in 1.34.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-73851/ (Markdown: https://insights.sbomify.com/CVE-2026-73851/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-73851
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-73851
- OSV: https://osv.dev/vulnerability/CVE-2026-73851

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-73851/
Summaries are generated and may contain mistakes; the official description above is the record.