From 7829ecf88d620ad50072053aa6bf79c642bde377 Mon Sep 17 00:00:00 2001 From: Vincent Biret Date: Mon, 17 Aug 2026 11:53:16 -0400 Subject: [PATCH] Improve GHSA-4vv7-jj25-4gh6 --- .../2026/07/GHSA-4vv7-jj25-4gh6/GHSA-4vv7-jj25-4gh6.json | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/advisories/github-reviewed/2026/07/GHSA-4vv7-jj25-4gh6/GHSA-4vv7-jj25-4gh6.json b/advisories/github-reviewed/2026/07/GHSA-4vv7-jj25-4gh6/GHSA-4vv7-jj25-4gh6.json index e7f22bd6c38..c7c4b3d36ea 100644 --- a/advisories/github-reviewed/2026/07/GHSA-4vv7-jj25-4gh6/GHSA-4vv7-jj25-4gh6.json +++ b/advisories/github-reviewed/2026/07/GHSA-4vv7-jj25-4gh6/GHSA-4vv7-jj25-4gh6.json @@ -1,13 +1,13 @@ { "schema_version": "1.4.0", "id": "GHSA-4vv7-jj25-4gh6", - "modified": "2026-08-17T14:55:49Z", + "modified": "2026-08-17T14:55:50Z", "published": "2026-07-24T16:12:14Z", "aliases": [ "CVE-2026-59866" ], "summary": "Microsoft Kiota: Arbitrary file write + code-injection via x-ms-kiota-info clientClassName and clientNamespaceName", - "details": "### Summary\n\nMicrosoft Kiota emitted the `x-ms-kiota-info` extension's `clientClassName` or `clientNamespaceName` value\n**raw**, with no identifier or path sanitization, as **both** the generated client's class/namespace name\n**and** part of the generated output path. When `kiota generate` is run **without `-c/--class-name`** — the\nzero-config workflow that `x-ms-kiota-info` is explicitly designed for (the API provider supplies the names in\nthe description so consumers don't have to) — an attacker who controls or tampers with the OpenAPI description\ncould therefore:\n\n- **(CWE-22) write the generated source file to a path outside the `-o` output directory** — e.g.\n `clientClassName: \"/var/www/html/shell\"`; and\n- **(CWE-94) inject arbitrary text into the generated class/namespace declaration**, corrupting the generated\n client.\n\nConfirmed on Kiota **1.32.4** (the self-contained `linux-x64` release binary), i.e. **after** the earlier\nwriter-sink hardening — that fix escaped property/enum/default/serialization sinks but never sanitized the\nprovider-supplied `clientClassName` / `clientNamespaceName`.\n\n### Details\n\n`clientClassName` reached two unsanitized sinks (observed in the generated C#; the same raw emission occurred\nfor Java, Go, TypeScript, Python, and PHP):\n\n```\n# output FILENAME (CWE-22): clientClassName flows into the file path\nclientClassName: \"/abs/path/PWNED\" -> /abs/path/PWNED.cs (written outside -o)\n\n# class declaration (CWE-94): clientClassName flows verbatim into the type declaration\nclientClassName: 'Pwn { } public class INJECTED { } public partial class RealClient'\n -> public partial class Pwn { } public class INJECTED { } public partial class RealClient : ... { }\n```\n\n`clientNamespaceName` reached the analogous namespace/path sinks.\n\n### Impact\n\nA developer or CI host generating a client from an attacker-controlled or compromised OpenAPI description\n(without `-c`) could create/overwrite a generated source file at an attacker-influenced path and emit\nattacker-controlled text into the generated client.\n\nThis does **not** reach clean remote code execution: because `clientClassName` is reused verbatim at multiple\nsites (the class name **and** the constructor name), injected code cannot be made to compile — it breaks the\nbuild. So the code-injection vector is a generation/build-corruption (integrity/DoS), and the high-severity\nprimitive is the file write. CWE-22 / CWE-94.\n\n### Patches\n\nFixed in **1.29.1 and 1.32.5** (https://github.com/microsoft/kiota/pull/7884). `clientClassName` and\n`clientNamespaceName` sourced from `x-ms-kiota-info` are now sanitized before use:\n`GenerationConfiguration.SanitizeClientClassName` strips any character outside `[A-Za-z0-9_]` and any invalid\nleading character (falling back to `ApiClient`), and `SanitizeClientNamespaceName` restricts to\n`[A-Za-z0-9._-]`, collapses consecutive dots, strips invalid leading characters (falling back to `ApiSdk`).\nThis removes path separators, drive/colon, `..`, quotes, and braces, so the values can no longer influence\nthe output path or inject into the declaration.\n\n### Remediation\n\nUpgrade to Kiota **1.29.1, 1.32.5,** or later and regenerate affected clients.", + "details": "### Summary\n\nMicrosoft Kiota emitted the `x-ms-kiota-info` extension's `clientClassName` or `clientNamespaceName` value\n**raw**, with no identifier or path sanitization, as **both** the generated client's class/namespace name\n**and** part of the generated output path. When `kiota generate` is run **without `-c/--class-name`** — the\nzero-config workflow that `x-ms-kiota-info` is explicitly designed for (the API provider supplies the names in\nthe description so consumers don't have to) — an attacker who controls or tampers with the OpenAPI description\ncould therefore:\n\n- **(CWE-22) write the generated source file to a path outside the `-o` output directory** — e.g.\n `clientClassName: \"/var/www/html/shell\"`; and\n- **(CWE-94) inject arbitrary text into the generated class/namespace declaration**, corrupting the generated\n client.\n\nConfirmed on Kiota **1.32.4** (the self-contained `linux-x64` release binary), i.e. **after** the earlier\nwriter-sink hardening — that fix escaped property/enum/default/serialization sinks but never sanitized the\nprovider-supplied `clientClassName` / `clientNamespaceName`.\n\n### Details\n\n`clientClassName` reached two unsanitized sinks (observed in the generated C#; the same raw emission occurred\nfor Java, Go, TypeScript, Python, and PHP):\n\n```\n# output FILENAME (CWE-22): clientClassName flows into the file path\nclientClassName: \"/abs/path/PWNED\" -> /abs/path/PWNED.cs (written outside -o)\n\n# class declaration (CWE-94): clientClassName flows verbatim into the type declaration\nclientClassName: 'Pwn { } public class INJECTED { } public partial class RealClient'\n -> public partial class Pwn { } public class INJECTED { } public partial class RealClient : ... { }\n```\n\n`clientNamespaceName` reached the analogous namespace/path sinks.\n\n### Impact\n\nA developer or CI host generating a client from an attacker-controlled or compromised OpenAPI description\n(without `-c`) could create/overwrite a generated source file at an attacker-influenced path and emit\nattacker-controlled text into the generated client.\n\nThis does **not** reach clean remote code execution: because `clientClassName` is reused verbatim at multiple\nsites (the class name **and** the constructor name), injected code cannot be made to compile — it breaks the\nbuild. So the code-injection vector is a generation/build-corruption (integrity/DoS), and the high-severity\nprimitive is the file write. CWE-22 / CWE-94.\n\n### Patches\n\nFixed in **1.32.5** (https://github.com/microsoft/kiota/pull/7884). `clientClassName` and\n`clientNamespaceName` sourced from `x-ms-kiota-info` are now sanitized before use:\n`GenerationConfiguration.SanitizeClientClassName` strips any character outside `[A-Za-z0-9_]` and any invalid\nleading character (falling back to `ApiClient`), and `SanitizeClientNamespaceName` restricts to\n`[A-Za-z0-9._-]`, collapses consecutive dots, strips invalid leading characters (falling back to `ApiSdk`).\nThis removes path separators, drive/colon, `..`, quotes, and braces, so the values can no longer influence\nthe output path or inject into the declaration.\n\n### Remediation\n\nUpgrade to Kiota **1.32.5** or later and regenerate affected clients.", "severity": [ { "type": "CVSS_V4", @@ -56,7 +56,7 @@ { "package": { "ecosystem": "NuGet", - "name": "Microsoft.OpenApi.Kiota" + "name": "Microsoft.OpenApi.Kiota.Builder" }, "ranges": [ { @@ -75,7 +75,7 @@ { "package": { "ecosystem": "NuGet", - "name": "Microsoft.OpenApi.Kiota.Builder" + "name": "Microsoft.OpenApi.Kiota" }, "ranges": [ {