{"id":"GHSA-4rj6-vrwv-wr8m","summary":"Microsoft Kiota Workspace-config poisoning: out-of-repo file write + generation-time SSRF","details":"### Summary\n\nMicrosoft Kiota honors a poisoned `.kiota/workspace.json` — the workspace configuration that Kiota's\ndocumented team workflow has developers commit to their repository — **unvalidated** on\n`kiota client generate` / `kiota plugin generate`. A repository (or pull request) containing a malicious\nper-client / per-plugin `outputPath` causes Kiota, when a developer or CI runs the documented regenerate\ncommand, to **(CWE-22) write the entire generated client to an arbitrary path outside the workspace** — the\n`outputPath` was not confined to the workspace root and absolute paths were accepted.\n\nConfirmed on Kiota **1.32.4** (`KIOTA_CONFIG_PREVIEW=true`, the self-contained `linux-x64` release binary).\n\n### Details\n\n```jsonc\n// .kiota/workspace.json (committed to the repo)\n\"clients\": { \"MyClient\": {\n   \"outputPath\": \"/abs/path/outside/repo/pwned_client\"   // -\u003e generated client written here (CWE-22)\n}}\n```\n\nRunning `kiota client generate --client-name MyClient` in the repo writes `MyClient.cs`,\n`P/PRequestBuilder.cs`, … to the attacker-chosen `outputPath` (verified outside the working tree).\n\n#### Note on `descriptionLocation`\n\nThe per-consumer `descriptionLocation` is intentionally fetched at generation time — this is how Kiota knows\nwhere to pull an updated description from when refreshing a client, the same way any other value in a\ncommitted lock/config file is honored. It is **not** treated as a vulnerability and is unchanged; only\n`outputPath` is now confined.\n\n### Impact\n\nA malicious or compromised repository — or a malicious PR that edits `.kiota/workspace.json` — leads to\narbitrary file write on the developer's or CI host's filesystem (overwrite source/build files, drop files in\nauto-loaded locations) whenever a teammate clones/pulls and runs the documented `kiota client generate` /\n`kiota plugin generate` to refresh the client. CWE-22.\n\nThis is a different trust boundary from the OpenAPI-description-based findings: the malicious input is the\nKiota **config**, not the spec.\n\n### Patches\n\nFixed in **1.29.1 and 1.32.5** (https://github.com/microsoft/kiota/pull/7885). On loading a workspace configuration,\neach client/plugin `outputPath` is validated to be a relative subdirectory of the workspace: null/empty,\nrooted paths (POSIX `/`, UNC `\\\\` / `//`, Windows drive `X:\\`), and any `..` traversal segment are rejected,\nand the resolved full path must stay under the workspace root. Generation aborts with an error if any\nconsumer's `outputPath` escapes the workspace.\n\n### Remediation\n\nUpgrade to Kiota **1.29.1, 1.32.5** or later. Review any committed workspace configs for `outputPath` values that\npoint outside the workspace.","aliases":["CVE-2026-59863"],"modified":"2026-08-17T15:00:08.071928611Z","published":"2026-07-24T16:11:24Z","database_specific":{"github_reviewed":true,"github_reviewed_at":"2026-07-24T16:11:24Z","nvd_published_at":"2026-07-16T15:16:35Z","cwe_ids":["CWE-22","CWE-829","CWE-918"],"severity":"HIGH"},"references":[{"type":"WEB","url":"https://github.com/microsoft/kiota/security/advisories/GHSA-4rj6-vrwv-wr8m"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-59863"},{"type":"WEB","url":"https://github.com/microsoft/kiota/pull/7885"},{"type":"WEB","url":"https://github.com/microsoft/kiota/commit/4049327872db7846ace35c9003774d3e3878e4e9"},{"type":"PACKAGE","url":"https://github.com/microsoft/kiota"},{"type":"WEB","url":"https://github.com/microsoft/kiota/releases/tag/v1.32.5"}],"affected":[{"package":{"name":"Microsoft.OpenApi.Kiota","ecosystem":"NuGet","purl":"pkg:nuget/Microsoft.OpenApi.Kiota"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"1.30.0"},{"fixed":"1.32.5"}]}],"versions":["1.30.0","1.31.0","1.31.1","1.32.0","1.32.1","1.32.2","1.32.3","1.32.4"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/07/GHSA-4rj6-vrwv-wr8m/GHSA-4rj6-vrwv-wr8m.json"}},{"package":{"name":"Microsoft.OpenApi.Kiota.Builder","ecosystem":"NuGet","purl":"pkg:nuget/Microsoft.OpenApi.Kiota.Builder"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"1.30.0"},{"fixed":"1.32.5"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/07/GHSA-4rj6-vrwv-wr8m/GHSA-4rj6-vrwv-wr8m.json"}},{"package":{"name":"Microsoft.OpenApi.Kiota","ecosystem":"NuGet","purl":"pkg:nuget/Microsoft.OpenApi.Kiota"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.29.1"}]}],"versions":["0.1.0-preview","0.1.1-preview","0.1.2-preview","0.1.3-preview","0.10.0-preview","0.11.0-preview","0.11.1-preview","0.2.0-preview","0.2.1-preview","0.3.0-preview","0.4.0-preview","0.5.0-preview","0.5.1-preview","0.6.0-preview","0.7.1-preview","0.8.3-preview","0.9.0-preview","1.0.0","1.0.1","1.1.0","1.1.1","1.1.2","1.1.3","1.10.0","1.10.1","1.11.0","1.11.1","1.12.0","1.13.0","1.14.0","1.15.0","1.16.0","1.17.0","1.18.0","1.19.0","1.19.1","1.2.0","1.2.1","1.20.0","1.21.0","1.22.0","1.22.1","1.22.2","1.22.3","1.23.0","1.24.0","1.24.1","1.24.2","1.24.3","1.25.1","1.26.0","1.26.1","1.27.0","1.28.0","1.29.0","1.3.0","1.4.0","1.5.0","1.5.1","1.6.1","1.7.0","1.8.0","1.8.1","1.8.2","1.9.0","1.9.1"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/07/GHSA-4rj6-vrwv-wr8m/GHSA-4rj6-vrwv-wr8m.json"}},{"package":{"name":"Microsoft.OpenApi.Kiota.Builder","ecosystem":"NuGet","purl":"pkg:nuget/Microsoft.OpenApi.Kiota.Builder"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.29.1"}]}],"versions":["0.2.0-preview","0.3.0-preview","0.4.0-preview","0.5.0-preview","0.5.1-preview","0.6.0-preview","0.7.1-preview","1.0.0","1.0.1","1.1.0","1.1.1","1.1.2","1.1.3","1.10.0","1.10.1","1.11.0","1.11.1","1.12.0","1.13.0","1.14.0","1.15.0","1.16.0","1.17.0","1.18.0","1.19.0","1.19.1","1.2.0","1.2.1","1.20.0","1.21.0","1.22.0","1.22.1","1.22.2","1.22.3","1.23.0","1.3.0","1.4.0","1.5.0","1.5.1","1.6.1","1.7.0","1.8.0","1.8.1","1.8.2","1.9.0","1.9.1"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/07/GHSA-4rj6-vrwv-wr8m/GHSA-4rj6-vrwv-wr8m.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:H/VA:L/SC:N/SI:N/SA:N"}]}