CVE-2026-59866Patch

LOWCVSS 9.3 · CRITICAL

Signal is active with 1 mentions in latest observed window

Immediate actions

  • Patch affected systems immediately

Recommended action window: Monitor and triage in normal cycle

NVD description

Kiota is an OpenAPI based HTTP Client code generator. Prior to 1.29.1 and 1.32.5, Kiota emitted x-ms-kiota-info clientClassName and clientNamespaceName values without identifier or path sanitization as both generated client class or namespace names and generated output path components when `kiota generate` ran without -c/--class-name, allowing an attacker-controlled or compromised OpenAPI description to write generated source outside the -o output directory and inject arbitrary text into generated class or namespace declarations. This issue is fixed in version 1.29.1 and 1.32.5 by GenerationConfiguration.SanitizeClientClassName and SanitizeClientNamespaceName.

0.5/ 10 priority

Sources & remediation

Weakness type (CWE)
CWE-22CWE-94

Priority

LOW

Exploitation

NONE

PoC

NONE

Patch

AVAILABLE

Momentum

NONE

Threat summary

  • Patch or workaround signal is available
  • 1 mentions across 1 observed day

What's happening

  • Patch or workaround mentioned in 1 signal
  • Technical details provided in 1 signal
  • 1 total mentions across 1 day

Deep dive

Activity timeline1 mentions / 1d
00111Mentions · 2026-07-16: 1Patch / Workaround · 2026-07-16: 1Technical Details · 2026-07-16: 107-16
Signal classification1 categories
Patch
1100.0%
Full discourse1 post
  • Upwind Security MDR@UpwindMDR
    Patch

    🚨Critical - Three Microsoft Kiota flaws from untrusted OpenAPI specs (CVE-2026-59864 / 59865 / 59866) Microsoft Kiota, the OpenAPI-based client and Copilot/Teams plugin generator, has three critical vulnerabilities before 1.32.5, all rooted in trusting attacker-controlled fields in an OpenAPI or plugin description (CVSS 9.3 each). - CVE-2026-59866: unsanitized clientClassName / clientNamespaceName during kiota generate enable path traversal outside the output directory and code injection into generated class/namespace declarations. - CVE-2026-59865: kiota info presents a spec-supplied dependencyInstallCommand as its recommended install command, leading to command injection when run. - CVE-2026-59864: kiota plugin add/generate write attacker-controlled static_template.file paths into Copilot/Teams manifests without validation, allowing path traversal / out-of-package file inclusion. All are triggered by running Kiota against a malicious OpenAPI/plugin description. Three separate bugs, one fix. 👉Upgrade Microsoft Kiota to 1.32.5 or later.

    Post summary

    Three critical CVEs (2026‑59864/59865/59866) in Microsoft Kiota are disclosed, with detailed technical impact, and a patch version 1.32.5 is recommended.

    00000100
    254 followersView on X

Explore more