How severe is CVE-2026-59863?

No CVSS score has been assigned to CVE-2026-59863 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-59863?

CVE-2026-59863 affects the following packages: Microsoft.OpenApi.Kiota (NuGet), Microsoft.OpenApi.Kiota.Builder (NuGet), Microsoft.OpenApi.Kiota (NuGet), Microsoft.OpenApi.Kiota.Builder (NuGet). Ecosystems affected: NuGet.

How do I fix CVE-2026-59863?

Update Microsoft.OpenApi.Kiota to 1.32.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-59863 is resolved across your whole dependency graph.

How do I detect CVE-2026-59863 in my NuGet dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Microsoft.OpenApi.Kiota. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate CVE-2026-59863 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against CVE-2026-59863?

O3 pinpoints whether CVE-2026-59863 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is CVE-2026-59863 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-59863 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What type of vulnerability is CVE-2026-59863?

CVE-2026-59863 is classified as Path Traversal (CWE-22). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2026-59863 published, and has it been updated?

CVE-2026-59863 was published on July 16, 2026 and was last updated on August 19, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

.NET NuGet

Not in CISA KEV

CVE-2026-59863

Fix: microsoft/kiota@4049327

CVE-2026-59863 is a Path Traversal vulnerability in Microsoft.OpenApi.Kiota. O3 Security confirms whether CVE-2026-59863 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.

Kiota: Workspace-config poisoning: out-of-repo file write + generation-time SSRF

Also known asGHSA-4rj6-vrwv-wr8m

Published

Jul 16, 2026

Updated

Aug 19, 2026

Affected

4 pkgs

Patched

4 / 4

Exploits

None indexed

Exploitation data as of Aug 19, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Real-World Exposure

4 pkgs affected

.NETMicrosoft.OpenApi.Kiota.NETMicrosoft.OpenApi.Kiota.Builder.NETMicrosoft.OpenApi.Kiota.NETMicrosoft.OpenApi.Kiota.Builder

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects NuGet packages — download data is not available via public APIs for these ecosystems.

Description

Kiota is an OpenAPI based HTTP Client code generator. Prior to 1.29.1 and 1.32.5, Kiota honored a poisoned .kiota/workspace.json workspace configuration without validating per-client or per-plugin outputPath values during kiota client generate and kiota plugin generate, allowing a malicious repository or pull request to use absolute paths, rooted POSIX / paths, UNC \ or // paths, Windows drive X:\ paths, or .. traversal segments to write generated client files outside the workspace root on a developer or CI host. This issue is fixed in version 1.29.1 and 1.32.5.

Affected Packages

4 total 4 fixed

Ecosystem	Package	Vulnerable range	Fix
.NETNuGet	`Microsoft.OpenApi.Kiota`	≥ 1.30.0&&< 1.32.5	1.32.5
.NETNuGet	`Microsoft.OpenApi.Kiota.Builder`	≥ 1.30.0&&< 1.32.5	1.32.5
.NETNuGet	`Microsoft.OpenApi.Kiota`	all versions	1.29.1
.NETNuGet	`Microsoft.OpenApi.Kiota.Builder`	all versions	1.29.1

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Microsoft.OpenApi.Kiota. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update Microsoft.OpenApi.Kiota to 1.32.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-59863 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-59863 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to CVE-2026-59863. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

Kiota is an OpenAPI based HTTP Client code generator. Prior to 1.29.1 and 1.32.5, Kiota honored a poisoned .kiota/workspace.json workspace configuration without validating per-client or per-plugin outputPath values during kiota client generate and kiota plugin generate, allowing a malicious repository or pull request to use absolute paths, rooted POSIX / paths, UNC \\ or // paths, Windows drive X:\ paths, or .. traversal segments to write generated client files outside the workspace root on a developer or CI host. This issue is fixed in version 1.29.1 and 1.32.5.

O3 Security · Impact-Aware SCA

Is CVE-2026-59863 in your dependencies?

O3 detects CVE-2026-59863 across NuGet dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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