{"id":"GHSA-gv5w-hfx8-8cwq","summary":"SeaweedFS: Filer JWT allowed_prefixes literal prefix match allows cross-tenant access to sibling paths","details":"### Impact\nWhen a filer JWT restricts a token to a set of path prefixes via `allowed_prefixes`, the authorization check used a literal byte-prefix match (`strings.HasPrefix`). A token scoped to `/tenant1` therefore also authorized requests to sibling paths such as `/tenant1234`, `/tenant1-old`, and `/tenant1backup`.\n\nIn a multi-tenant deployment this lets the holder of one tenant's token access another tenant's data. Because `allowed_prefixes` gates both read and write tokens, the impact covers cross-tenant reads and writes. A valid scoped token is required, so this is an authorization bypass rather than a fully unauthenticated flaw.\n\n### Affected component\n- `weed/server/filer_server_handlers.go` (JWT `allowed_prefixes` authorization check)\n\n### Patches\nFixed in **4.24**. The check now matches on `/`-separated path components after `path.Clean` normalisation, so `/tenant1` authorizes only `/tenant1` and its descendants — not `/tenant1234` or other sibling paths.\n\n### Workarounds\nWhere feasible, choose prefix names that are not string-prefixes of one another (e.g. keep a trailing separator convention). Upgrade to 4.24.\n\n### References\n- Reported by Kadir Arslan (https://github.com/KadirArslan)","aliases":["BIT-seaweedfs-2026-72921","CVE-2026-72921","GO-2026-6361"],"modified":"2026-09-10T15:25:33.076515113Z","published":"2026-09-02T23:42:05Z","database_specific":{"github_reviewed_at":"2026-09-02T23:42:05Z","nvd_published_at":"2026-08-11T15:17:38Z","cwe_ids":["CWE-863"],"severity":"HIGH","github_reviewed":true},"references":[{"type":"WEB","url":"https://github.com/seaweedfs/seaweedfs/security/advisories/GHSA-gv5w-hfx8-8cwq"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-72921"},{"type":"WEB","url":"https://github.com/seaweedfs/seaweedfs/pull/9439"},{"type":"WEB","url":"https://github.com/seaweedfs/seaweedfs/commit/05ed5c9ae8a2a45101b52b61d02f170d20d587ff"},{"type":"PACKAGE","url":"https://github.com/seaweedfs/seaweedfs"},{"type":"WEB","url":"https://github.com/seaweedfs/seaweedfs/releases/tag/4.24"}],"affected":[{"package":{"name":"github.com/seaweedfs/seaweedfs","ecosystem":"Go","purl":"pkg:golang/github.com/seaweedfs/seaweedfs"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"0.0.0-20260512171048-05ed5c9ae8a2"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/09/GHSA-gv5w-hfx8-8cwq/GHSA-gv5w-hfx8-8cwq.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:H/A:N"}]}