GitHub Advisoryadvisory · Go
GHSA-gv5w-hfx8-8cwq SeaweedFS: Filer JWT allowed_prefixes literal prefix match allows cross-tenant access to sibling paths
HIGH
Official page ↗
- Aliases
- CVE-2026-72921
- Ecosystem
- Go
- Packages
- github.com/seaweedfs/seaweedfs
- Severity
- High
- CVSS vector
- CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
- Weaknesses
- CWE-863
- Reviewed
- 2026-09-02
Affected packages
• Go github.com/seaweedfs/seaweedfs: < 0.0.0-20260512171048-05ed5c9ae8a2 → fixed in 0.0.0-20260512171048-05ed5c9ae8a2
Description
Impact
When 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`.
In 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.
Affected component
• `weed/server/filer_server_handlers.go` (JWT `allowed_prefixes` authorization check)
Patches
Fixed 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.
Workarounds
Where feasible, choose prefix names that are not string-prefixes of one another (e.g. keep a trailing separator convention). Upgrade to 4.24.
References
• Reported by Kadir Arslan (https://github.com/KadirArslan)
Related
Alias · CVE (1)
- CVE-2026-72921 SeaweedFS is a distributed storage system. vulnerability
Weakness · CWE (1)
- CWE-863 Incorrect Authorization weakness
References
- https://github.com/seaweedfs/seaweedfs/security/advisories/GHSA-gv5w-hfx8-8cwq web
- https://nvd.nist.gov/vuln/detail/CVE-2026-72921 advisory
- https://github.com/seaweedfs/seaweedfs/pull/9439 web
- https://github.com/seaweedfs/seaweedfs/commit/05ed5c9ae8a2a45101b52b61d02f170d20d587ff web
- https://github.com/seaweedfs/seaweedfs package
- https://github.com/seaweedfs/seaweedfs/releases/tag/4.24 web