Microsoft Kiota: XML Doc-Comment Newline Breakout Code Injection
CVE-2026-59860GHSA-3hrf-2gc2-mx32
What to do
Vendor fix available. Upgrade each affected package to the fixed version on its release line (microsoft.openapi.kiota 1.32.3, 1.29.1; microsoft.openapi.kiota.builder 1.32.3, 1.29.1), redeploy, then verify what is actually installed.
This page has no inventory attached, so it cannot say whether you are affected. A vendor fix is not proof that your deployment is fixed.
Affected packages
NuGet microsoft.openapi.kiota
- Affected
- >= 1.30.0, < 1.32.3< 1.29.1
- Fixed in
- 1.29.1, 1.32.3
NuGet microsoft.openapi.kiota.builder
- Affected
- >= 1.30.0, < 1.32.3< 1.29.1
- Fixed in
- 1.29.1, 1.32.3
Sources
- GitHub Advisory Database and maintainer security advisories on GitHub
GitHub-reviewed advisory GHSA-3hrf-2gc2-mx32 lists affected ranges: NuGet microsoft.openapi.kiota >=1.30.0 =0 =1.30.0 =0 <1.29.1
VerifiedObserved Structured GitHub Advisory Database record (type=reviewed) from the GitHub REST API.
Severity and exploitation
- Exploitation
- No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
- CVSS 4.0
- 8.7 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N · score source
- EPSS
- CVE-2026-59860: 1.38% estimated exploitation activity in the next 30 days; percentile 72.18 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.
Source description
As published by the source; long descriptions are shortened.
Summary Kiota versions prior to 1.32.3 and 1.29.1 are affected by a code-generation injection vulnerability in the C
XML documentation-comment sink (the description, externalDocs label, and externalDocs link fields emitted as /// … comments). When text from an OpenAPI description is written into single-line XML doc comments without stripping newline and Unicode line-terminator characters, an attacker can break out of the /// comment line and inject additional code into generated C
clients. Impact and Preconditions This issue is only practically exploitable when: 1. the OpenAPI description used for generation is from an untrusted source, or 2. a normally trusted OpenAPI description has been compromised/tampered with. The injected code is compiled (and may execute) when the developer or CI builds the generated client. If you only generate from trusted, integrity-protected API descriptions, risk is significantly reduced. Affected Versions - Affected: all versions < 1.29.1, = 1.30.0, <…
Dates and revisions
- Published by the source
- Last modified by the source
- Source last checked
- Revision 1 · created ·
Published from ghsa record GHSA-3hrf-2gc2-mx32
Agent brief
Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.
# Patch Next advisory brief: CVE-2026-59860 Advisory: Microsoft Kiota: XML Doc-Comment Newline Breakout Code Injection IDs: CVE-2026-59860, GHSA-3hrf-2gc2-mx32 Record: https://patchnext.com/advisories/cve-2026-59860 (revision 1, source checked 26 Oct 2026, 17:05 UTC) Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected. Severity: High (CVSS 8.7) Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV. Vendor response: Vendor fix available; fixed versions by package: microsoft.openapi.kiota 1.32.3, 1.29.1; microsoft.openapi.kiota.builder 1.32.3, 1.29.1. A vendor fix does not mean a deployment is fixed. ## Affected components - NuGet microsoft.openapi.kiota: affected >= 1.30.0, < 1.32.3; < 1.29.1; fixed in 1.29.1, 1.32.3 - NuGet microsoft.openapi.kiota.builder: affected >= 1.30.0, < 1.32.3; < 1.29.1; fixed in 1.29.1, 1.32.3 ## Suggested inspection (read-only) - NuGet microsoft.openapi.kiota: check the installed version with your package manager. - NuGet microsoft.openapi.kiota.builder: check the installed version with your package manager. ## Supported action Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version. ## Required regression checks - Run the test suite and a production build. - Exercise the features that depend on microsoft.openapi.kiota, microsoft.openapi.kiota.builder. - Repeat the inspection and confirm that only fixed versions remain installed. ## Rollback considerations - Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward. ## Unresolved questions - Which deployments run an affected version? - Exploitation status can change. Check again before lowering the priority. - Mark the work resolved only after the fixed version is verified in production. ## Sources - Verified: https://github.com/advisories/GHSA-3hrf-2gc2-mx32 (GitHub-reviewed advisory GHSA-3hrf-2gc2-mx32 lists affected ranges: NuGet microsoft.openapi.kiota >=1.30.0 =0 =1.30.0 =0 <1.29.1) Commands are suggestions: review each one before running it.
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