CVE-2026-55873 is a medium-severity (CVSS 4.3) CWE-863 vulnerability in github.com/seaweedfs/seaweedfs. A fix is available for github.com/seaweedfs/seaweedfs — see the affected versions and patch details below.
SeaweedFS: Improper authorization in the S3Tables / Iceberg REST management API lets a low-privileged S3 user enumerate administrator-owned table buckets
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-55873.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2026-55873 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 386,684 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
github.com/seaweedfs/seaweedfsReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
Summary
SeaweedFS routes requests signed with SigV4 service s3tables to the S3Tables
management API. Authorization on that path collapsed account-less S3 identities
into the shared admin account and failed open, so a user holding only ordinary
S3 Read credentials — and no S3Tables-specific permission — could invoke
S3Tables management operations such as GET /buckets and enumerate
administrator-owned table bucket inventory (names and ARNs). The same handler
backs the Iceberg REST catalog, which was affected by the same flaw.
Impact
An authenticated low-privileged S3 user can cross the boundary between ordinary S3 object access and S3Tables management. Confirmed impact is disclosure of administrator-owned table bucket inventory (bucket names and ARNs); in shared or multi-tenant deployments this can reveal tenant naming and operational structure.
Affected versions
SeaweedFS >= 4.08, < 4.34 (the S3Tables management API was introduced in 4.08).
Patched versions
Fixed in 4.34 (#9961). Administrator status is now decided by the
ACTION_ADMIN capability rather than by a collapsed admin account id, S3Tables
authorization no longer defaults to allow, and the tautological ListTableBuckets
gate was removed. Related hardening of the same root cause landed in #9962,
#9963, and #9971.
Workaround
No configuration workaround — upgrade to 4.34 or later.
Credit
Reported by TA-MU-TA.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/seaweedfs/seaweedfs | ≥ 0.0.0-20260128085517-09bb90e8dc16&&< 0.0.0-20260614205536-b13463880c1f | 0.0.0-20260614205536-b13463880c1fgo get github.com/seaweedfs/seaweedfs@v0.0.0-20260614205536-b13463880c1f |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/seaweedfs/seaweedfs, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/seaweedfs/seaweedfs to 0.0.0-20260614205536-b13463880c1f or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-55873 is resolved across your whole dependency graph.
Workarounds
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.
Frequently Asked Questions
Is CVE-2026-55873 in your dependencies?
Find it across Go, including transitive dependencies.