{"id":"GHSA-68j5-4m99-w9w9","summary":"File Browser has an Authorization Policy Bypass in Public Share Download Flow","details":"### Summary\nA permission enforcement flaw allows users without download privileges (`download=false`) to still expose and retrieve file content via public share links when they retain share privileges (`share=true`). This bypasses intended access control policy and enables unauthorized data exfiltration to unauthenticated users. Where download restrictions are used for data-loss prevention or role separation.\n\n### Details\nThe backend applies inconsistent authorization checks across download paths:\n\n- Direct raw download correctly enforces `Perm.Download`:\n  - [[raw.go](https://github.com/filebrowser/filebrowser/blob/master/http/raw.go#82)](filebrowser/http/raw.go:82)\n- Share creation only enforces `Perm.Share`:\n  - [[share.go](https://github.com/filebrowser/filebrowser/blob/master/http/share.go#21)](filebrowser/http/share.go:21)\n- Public share/download handlers serve shared content without verifying owner `Perm.Download`:\n  - [public.go](https://github.com/filebrowser/filebrowser/blob/master/http/public.go#18)(filebrowser/http/public.go:18)\n  - [public.go](https://github.com/filebrowser/filebrowser/blob/master/http/public.go#116)(filebrowser/http/public.go:116)\n\nAs a result, a user who is blocked from direct downloads can create a share and obtain the same file via `/api/public/dl/\u003chash\u003e`.\n\n### PoC\n\n1. Create a non-admin user with:\n- `perm.share = true`\n- `perm.download = false`\n\n2. Login as that user and upload a **PDF** file:\n- `POST /api/resources/nodl_secret_\u003crand\u003e.pdf` with `Content-Type: application/pdf`\n\n3. Verify direct raw download is denied:\n- `GET /api/raw/nodl_secret_\u003crand\u003e.pdf`\n- Expected and observed: `202 Accepted` (blocked)\n\n4. Create share for same file:\n- `POST /api/share/nodl_secret_\u003crand\u003e.pdf`\n- Observed: `200`, response includes `hash` (example: `qxfK3JMG`)\n\n5. Download publicly without authentication:\n- `GET /api/public/dl/\u003chash\u003e`\n- Observed (vulnerable): `200`, `Content-Type: application/pdf`, and PDF bytes are returned\n\nLive evidence captured (March 1, 2026):\n- `create user`: `201`\n- `create file`: `200`\n- `direct /api/raw`: `202 Accepted`\n- `create share`: `200`\n- `public download /api/public/dl/mxK-ppZb`: `200`\n- `public download content-type`: `application/pdf`\n- `public download body length`: `327` bytes\n\n### Impact\nThis is an **access control / authorization policy bypass** vulnerability.\n\n- **Who can exploit:** Any authenticated user granted `share=true` but denied `download`.\n- **Who is impacted:** Operators and organizations relying on download restrictions to prevent data export.\n- **What can happen:** Restricted users can still distribute and retrieve files publicly, including unauthenticated access through share URLs.","aliases":["CVE-2026-32761","GO-2026-4738"],"modified":"2026-08-24T00:36:28.374877865Z","published":"2026-03-18T12:59:12Z","database_specific":{"nvd_published_at":"2026-03-20T00:16:17Z","cwe_ids":["CWE-284","CWE-639","CWE-863"],"severity":"MODERATE","github_reviewed":true,"github_reviewed_at":"2026-03-18T12:59:12Z"},"references":[{"type":"WEB","url":"https://github.com/filebrowser/filebrowser/security/advisories/GHSA-68j5-4m99-w9w9"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-32761"},{"type":"WEB","url":"https://github.com/filebrowser/filebrowser/commit/09a26166b4f79446e7174c017380f6db45444e32"},{"type":"PACKAGE","url":"https://github.com/filebrowser/filebrowser"},{"type":"WEB","url":"https://github.com/filebrowser/filebrowser/releases/tag/v2.62.0"}],"affected":[{"package":{"name":"https://github.com/filebrowser/filebrowser","ecosystem":"Go","purl":"pkg:golang/https:/github.com/filebrowser/filebrowser"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"last_affected":"2.61.0"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/03/GHSA-68j5-4m99-w9w9/GHSA-68j5-4m99-w9w9.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N"}]}