CVE-2026-59867 Kiota: Generation-time SSRF + remote/local file inclusion via unrestricted $ref
Attackers can trigger SSRF and file inclusion during code generation by manipulating OpenAPI $ref values, potentially leaking data or executing code.
- 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-2026-59867?
CVE-2026-59867 is a high-severity server-side request forgery vulnerability in microsoft kiota, published on 16 Jul 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 1.32.5, Kiota resolved OpenAPI $ref values by fetching remote http(s) URLs and reading local absolute or out-of-tree file paths, allowing `kiota generate` on an attacker-controlled or attacker-influenced description to perform build-time SSRF, remote file inclusion, and local file inclusion by inlining external schemas such as REMOTE_KIOTA_PROP or Leaked into generated clients. This issue is fixed in version 1.29.1 and 1.32.5 by AllowedExternalOriginsStreamLoader and the --allowed-external-origins option.
Which versions are affected by CVE-2026-59867?
8 open source packages ship an affected version, including Microsoft.OpenApi.Kiota and Microsoft.OpenApi.Kiota.Builder.
| 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 | 1.32.5 |
Microsoft.OpenApi.Kiota NuGet | From 1.30.0 | 1.32.5 |
Microsoft.OpenApi.Kiota.Builder NuGet | All versions | 1.29.1 |
Microsoft.OpenApi.Kiota.Builder NuGet | All versions | 1.29.1 |
2 more packages
Microsoft.OpenApi.Kiota.Builder NuGet | From 1.30.0 | 1.32.5 |
Microsoft.OpenApi.Kiota.Builder NuGet | From 1.30.0 | 1.32.5 |
How do I fix CVE-2026-59867?
Upgrade Microsoft.OpenApi.Kiota to a fixed version for your release line: 1.29.1 or 1.32.5.
Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.
Is CVE-2026-59867 being exploited?
There is no known exploitation of CVE-2026-59867 in the wild and no public exploit code.
Sources
Also known as GHSA-rg4h-fpcp-2qm8.