Which versions of Microsoft Kiota are affected by EUVD-2026-44928?

Microsoft Kiota's PHP code generator in versions prior to 1.32.4 contains a code injection vulnerability that enables arbitrary PHP code execution in production environments.. A patch is available.

How to fix or mitigate EUVD-2026-44928?

Within 24 hours, inventory all Microsoft Kiota instances with PHP code generation enabled, identify external or third-party OpenAPI specifications being consumed, and verify current versions. Although no public exploit identified at time of analysis, the high technical impact warrants prompt remediation; vendor-released patch 1.32.4 addresses the vulnerability. Within 7 days, upgrade all Kiota deployments to version 1.32.4 or later, regenerate PHP client libraries from external specifications using the patched version, conduct security review of generated code, and redeploy to production. Within 30 days, mandate code review for all generated client libraries before deployment, restrict code generation to validated internal API specifications only, and implement automated scanning to detect suspicious variable interpolation in generated PHP files.

Microsoft Kiota EUVD-2026-44928

Q: What is the CVSS score of EUVD-2026-44928?

EUVD-2026-44928 has a CVSS 4.0 base score of 8.7 (High). CVSS vector: 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. EPSS exploitation probability: 1.0%.

| CVE-2026-59859 HIGH

Code Injection (CWE-94)

2026-07-16 GitHub_M

GHSA-jqwh-526h-c92j

PHP RCE Code Injection Kiota

8.7

CVSS 4.0 · Vendor: GitHub_M

Severity by source

Vendor (GitHub_M) PRIMARY

8.7 HIGH

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

vuln.today AI

9.6 CRITICAL

Malicious spec delivered remotely (AV:N, PR:N), developer must run generator (UI:R), generated code executes in PHP runtime beyond Kiota's trust boundary (S:C), enabling full RCE (C:H/I:H/A:H).

3.1 AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

4.0 AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Primary rating from Vendor (GitHub_M).

CVSS VectorVendor: GitHub_M

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Scope

Lifecycle Timeline

Patch available

Jul 16, 2026 - 17:03 EUVD

Source Code Evidence Fetched

Jul 16, 2026 - 15:03 vuln.today

Analysis Generated

Jul 16, 2026 - 15:03 vuln.today

CVE Published

Jul 16, 2026 - 14:40 cve.org

HIGH 8.7

DescriptionCVE.org

Kiota is an OpenAPI based HTTP Client code generator. Prior to 1.32.4, Kiota's PHP generator embedded OpenAPI description, default fields, property names, and other schema-derived strings into PHP double-quoted literals through SanitizeDoubleQuote() in Writers/StringExtensions.cs without escaping $, allowing attacker-controlled ${...}, $var, or {$obj->prop} interpolation constructs to inject arbitrary PHP code into generated model and request-builder classes. This issue is fixed in version 1.32.4.

AnalysisAI

PHP code generation in Microsoft Kiota prior to 1.32.4 permits injection of arbitrary PHP code when the generator processes attacker-controlled OpenAPI specification fields, because the shared SanitizeDoubleQuote() helper in Writers/StringExtensions.cs fails to escape the $ character before embedding schema-derived strings into PHP double-quoted literals. Developers or CI/CD pipelines that generate PHP API clients from untrusted or third-party specifications will produce PHP files containing live interpolation expressions (${...}, $var, {$obj->prop}) that execute attacker-chosen code at PHP runtime in production environments. No public exploit has been identified and SSVC rates exploitation as currently none, but technical impact is rated total; the realistic risk is tightly gated on whether teams consume external or attacker-influenced specs without generated-code review.

Technical ContextAI

Kiota is Microsoft's OpenAPI-based HTTP client code generator that produces typed API clients across multiple languages, distributed via NuGet as Microsoft.OpenApi.Kiota and Microsoft.OpenApi.Kiota.Builder. The vulnerability resides in the shared SanitizeDoubleQuote() function (CWE-94: Improper Control of Code Generation), which strips double-quote characters from OpenAPI schema-derived strings before embedding them into generated source code but never escapes the $ character. PHP's double-quoted string literals natively evaluate interpolation constructs - ${expression}, $variable, and {$object->property} - at runtime, meaning any schema field (description, default values, enum wire-names, discriminator property names, Accept header values, request body content types, query-parameter serialization names) that contains a $-prefixed construct is emitted verbatim into generated PHP model and request-builder classes. The fix, introduced in commit 5e2a211ac4261988fbdc72c3b268596ea8837b87 via PR #7863, adds PhpConventionService.SanitizePhpDoubleQuoteLiteral() which chains SanitizeDoubleQuote() with .Replace("$", "\\$"). This is a recurrence of a previously fixed literal-injection class: the Ruby generator had an analogous # interpolation fix, and the PHP $ variant was a missed sibling in the sanitizer helper.

RemediationAI

Upgrade Microsoft.OpenApi.Kiota and Microsoft.OpenApi.Kiota.Builder NuGet packages to version 1.32.4 or later; for projects pinned to the older branch, upgrade to 1.29.1. The patch is confirmed at https://github.com/microsoft/kiota/releases/tag/v1.32.4 and the fix commit is 5e2a211ac4261988fbdc72c3b268596ea8837b87. After upgrading, regenerate all PHP client code to replace previously generated files that may contain unescaped interpolation constructs. If immediate upgrade is not feasible, apply three compensating controls: first, audit all OpenAPI specification files consumed by the generator for $ characters in description fields, default values, property wire-names, enum values, and header values, removing or escaping suspicious strings before generation; second, implement mandatory code review of all generated PHP files, scanning double-quoted strings for ${, $varname, or {$ patterns before merging any branch; third, restrict code generation strictly to fully trusted, internally authored OpenAPI specifications and block automated regeneration from remote or third-party spec URLs. Each control degrades gracefully if bypassed, so layer all three when patching is delayed.