SeaweedFS: Filer JWT allowed_prefixes literal prefix match allows cross-tenant access to sibling paths

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SeaweedFS is a distributed storage system. Prior to 4.24, the weed/server/filer_server_handlers.go allowed_prefixes authorization check used strings.HasPrefix on raw path strings, so a filer JWT scoped to /tenant1 also authorized sibling paths such as /tenant1234, /tenant1-old, and /tenant1backup, enabling cross-tenant reads and writes with a valid scoped token. This issue is fixed in version 4.24.

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11 Aug 2026 14:28:49 UTC

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13 Aug 2026 15:14:54 UTC

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23 Oct 2026 15:48:27 UTC

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CVSS 3.1 · 8.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

SeaweedFS is a distributed storage system. Prior to 4.24, the weed/server/filer_server_handlers.go allowed_prefixes authorization check used strings.HasPrefix on raw path strings, so a filer JWT scoped to /tenant1 also authorized sibling paths such as /tenant1234, /tenant1-old, and /tenant1backup, enabling cross-tenant reads and writes with a valid scoped token. This issue is fixed in version 4.24.

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Aug 11, 2026, 2:28:49 PM (timezone not stated)

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Aug 13, 2026, 3:14:54 PM (timezone not stated)

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14 Nov 2026 03:06:20 UTC

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EUVD CVSS 3.1 · 8.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

SeaweedFS is a distributed storage system. Prior to 4.24, the weed/server/filer_server_handlers.go allowed_prefixes authorization check used strings.HasPrefix on raw path strings, so a filer JWT scoped to /tenant1 also authorized sibling paths such as /tenant1234, /tenant1-old, and /tenant1backup, enabling cross-tenant reads and writes with a valid scoped token. This issue is fixed in version 4.24.

Source published

11 Aug 2026 15:17:38 UTC

Source modified

9 Sep 2026 20:46:02 UTC

Saved here

25 Oct 2026 15:19:03 UTC

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CVSS 3.1 · [email protected] · Secondary · 8.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

### 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)

Source published

2 Sep 2026 23:42:05 UTC

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10 Sep 2026 15:25:33 UTC

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24 Oct 2026 13:19:41 UTC

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GitHub Advisory Database · CC-BY-4.0

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CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

Publisher rating · HIGH

SeaweedFS: Filer JWT allowed_prefixes literal prefix match allows cross-tenant access to sibling paths in github.com/seaweedfs/seaweedfs

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10 Sep 2026 14:48:42 UTC

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10 Sep 2026 15:25:33 UTC

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24 Oct 2026 13:19:41 UTC

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OSV · upstream source license applies

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