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.
- 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
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.
Which versions are affected by CVE-2026-73851?
4 open source packages ship an affected version, including Microsoft.OpenApi.Kiota.
| Package | 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.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-73851 being exploited?
There is no known exploitation of CVE-2026-73851 in the wild and no public exploit code.
Sources
Also known as GHSA-p5rm-jg5c-8c77.