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GHSA-jqwh-526h-c92j

Fix: microsoft/kiota#7863

GHSA-jqwh-526h-c92j is a Code Injection vulnerability in Microsoft.OpenApi.Kiota. O3 Security confirms whether GHSA-jqwh-526h-c92j is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.

Microsoft Kiota: Code Generation Literal Injection in Kiota PHP Generator

Also known asCVE-2026-59859
Published
Jul 24, 2026
Updated
Aug 17, 2026
Affected
4 pkgs
Patched
4 / 4
Exploits
None indexed
Exploitation data as of Aug 17, 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

Impact

The Kiota PHP code generator is vulnerable to a code generation literal injection attack. The generator embeds string values from OpenAPI fields (e.g. description, default values, and property names) directly into PHP double-quoted string literals without properly escaping the $ character. Since PHP evaluates string interpolation expressions like "${expr}", "$var", and "{$obj->prop}" within double-quoted strings at runtime, an attacker who controls an OpenAPI specification file can inject arbitrary PHP code into generated model and request-builder classes.

Who is impacted

Developers using Kiota to generate PHP API clients from external or untrusted OpenAPI specifications

Teams with CI/CD pipelines configured to automatically regenerate client code from remote specs

Applications that deploy generated PHP code to production servers

Vulnerability details

Affected component: StringExtensions.cs

Root cause: The shared SanitizeDoubleQuote() function in Writers/StringExtensions.cs does not escape the $ character. As a result, any schema-derived string emitted as a PHP double-quoted literal preserves $-prefixed interpolation constructs (${...}, $var, {$...}) verbatim, which PHP evaluates at runtime instead of treating as literal text. This is the same class of code-generation literal-injection flaw previously fixed for the Ruby generator (# interpolation), recurring here as a missed variant for PHP's $ interpolation in the sibling sanitizer helper.

Attack vectors

OpenAPI description and default fields in schema properties

Property wire-name keys embedded in deserializer/serializer methods

Any schema-derived string embedded in PHP double-quoted literals

Severity: Critical when generated code reaches production; High for CI/CD environments with access to production secrets; Medium for public third-party specs; Low for developer-controlled specs.

Patches

#7863

Workarounds

If you cannot upgrade immediately:

  1. Audit and sanitize OpenAPI specifications: Review all OpenAPI specification files for any descriptions, default values, or property names containing the $ character. Remove or replace any suspicious strings before code generation.
  2. Code review of generated files: Implement mandatory code review of all generated PHP files before merging into any branch. Look for double-quoted strings containing ${, $var, or {$ patterns.
  3. Restrict specification sources: Only consume OpenAPI specifications from trusted internal sources. Avoid automatic code generation from external or third-party APIs until this patch is applied.
  4. Isolate generated code from production: Do not deploy generated PHP models to production environments unless the specification source has been verified and reviewed.
  5. Manual escaping (temporary): If regeneration is not possible, manually inspect and edit generated files to escape any $ characters in double-quoted string literals (replace $ with \$).

Remediation

Upgrade Kiota to 1.29.1, 1.32.4, or later.

Regenerate/refresh existing generated clients as a precaution:

Refreshing generated clients ensures previously generated vulnerable code is replaced with hardened output.

Affected Packages

4 total 4 fixed
EcosystemPackageVulnerable rangeFix
.NETNuGetMicrosoft.OpenApi.Kiota1.30.0&&< 1.32.41.32.4
.NETNuGetMicrosoft.OpenApi.Kiota.Builder1.30.0&&< 1.32.41.32.4
.NETNuGetMicrosoft.OpenApi.Kiotaall versions1.29.1
.NETNuGetMicrosoft.OpenApi.Kiota.Builderall versions1.29.1

Detection & mitigation playbook

Open-source dependency
  1. 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.

  2. Fix

    Update Microsoft.OpenApi.Kiota to 1.32.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-jqwh-526h-c92j is resolved across your whole dependency graph.

  3. 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.

  4. How O3 protects you

    O3 pinpoints whether GHSA-jqwh-526h-c92j 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 GHSA-jqwh-526h-c92j. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

# Impact The Kiota PHP code generator is vulnerable to a code generation literal injection attack. The generator embeds string values from OpenAPI fields (e.g. `description`, default values, and property names) directly into PHP double-quoted string literals without properly escaping the `$` character. Since PHP evaluates string interpolation expressions like `"${expr}"`, `"$var"`, and `"{$obj->prop}"` within double-quoted strings at runtime, an attacker who controls an OpenAPI specification file can inject arbitrary PHP code into generated model and request-builder classes. # Who is impacte
O3 Security · Impact-Aware SCA

Is GHSA-jqwh-526h-c92j in your dependencies?

O3 detects GHSA-jqwh-526h-c92j across NuGet dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

GHSA-jqwh-526h-c92j: Microsoft.OpenApi.Kiota | O3 Security