# CVE-2026-72921: SeaweedFS: Filer JWT allowed_prefixes literal prefix match allows cross-tenant access to sibling paths

> Attackers with a scoped JWT can access sibling tenant paths due to flawed prefix matching, enabling cross-tenant data access.

- **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 11 Aug 2026
- **Updated:** 13 Aug 2026
- **Also known as:** BIT-seaweedfs-2026-72921, GHSA-gv5w-hfx8-8cwq, GO-2026-6361, MINI-47cq-q2wm-xq4m, MINI-fmfq-w4w4-jp9c

## What is CVE-2026-72921?

CVE-2026-72921 is a high-severity authentication bypass vulnerability in seaweedfs, published on 11 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

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.

Weakness: CWE-863 (Incorrect Authorization)

## Which versions are affected by CVE-2026-72921?

4 open source packages ship an affected version, including github.com/seaweedfs/seaweedfs and seaweedfs.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/seaweedfs/seaweedfs` | Go | All versions | 0.0.0-20260512171048-05ed5c9ae8a2 |
| `github.com/seaweedfs/seaweedfs` | Go | All versions | 0.0.0-20260512171048-05ed5c9ae8a2 |
| `github.com/seaweedfs/seaweedfs` | Go | All versions | 0.0.0-20260512171048-05ed5c9ae8a2 |
| `seaweedfs` | Bitnami | All versions | 4.24.0 |

## How do I fix CVE-2026-72921?

Upgrade github.com/seaweedfs/seaweedfs to 0.0.0-20260512171048-05ed5c9ae8a2 or later.

## Is CVE-2026-72921 being exploited?

There is no known exploitation of CVE-2026-72921 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-72921 and fix it if it is affected.

What it is: CVE-2026-72921 is a high-severity authentication bypass vulnerability in seaweedfs, published on 11 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-72921 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/seaweedfs/seaweedfs (Go): affected all versions; fixed in 0.0.0-20260512171048-05ed5c9ae8a2
- github.com/seaweedfs/seaweedfs (Go): affected all versions; fixed in 0.0.0-20260512171048-05ed5c9ae8a2
- github.com/seaweedfs/seaweedfs (Go): affected all versions; fixed in 0.0.0-20260512171048-05ed5c9ae8a2
- seaweedfs (Bitnami): affected all versions; fixed in 4.24.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-72921/ (Markdown: https://insights.sbomify.com/CVE-2026-72921/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-72921
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-72921
- OSV: https://osv.dev/vulnerability/CVE-2026-72921

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-72921/
Summaries are generated and may contain mistakes; the official description above is the record.