SeaweedFS: Path traversal in the S3 gateway X-Amz-Copy-Source header allows cross-bucket object read — GHSA-56WQ-X3WV-3FF4

Summary

### Summary The SeaweedFS S3 API gateway did not reject `..` path segments in the `X-Amz-Copy-Source` header used by `CopyObject` and `UploadPartCopy`. The request URL path was hardened against traversal in 4.30 (CVE-2026-54917), but the copy-source header was only checked for emptiness, so a `..` segment in the copy source survived into the server-side filer path and resolved into a different bucket. ### Impact A…

Timeline

Published by source

2026-08-28

Risk context

• Reported severity or threat level: high.
• Reported CVSS score: 7.7 out of 10.
• Reported EPSS value: 0.00606.
• Review exposure for the affected product or family: go: github.com/seaweedfs/seaweedfs.

Product

go: github.com/seaweedfs/seaweedfs

What to do

General, cautious steps (verify details in the official source):

• Prioritize patching or mitigation immediately (treat as actively risky).
• Identify affected product versions in your inventory and verify whether you are impacted.
• Apply vendor patches/updates or recommended mitigations as soon as available.
• Read the official advisory for exact affected versions and remediation steps.

Official advisory

• Read the official source
• CVE Record
• NVD

Evidence and provenance

Canonical advisory ID

GHSA-56WQ-X3WV-3FF4

Source

GitHub

Vendor

GitHub

Published by source

2026-08-28

Last source activity

2026-08-28

Additional identifiers

CVE-2026-55874

Curated by

hlukh.ch

Related advisories and connections

These advisories are connected by shared CVE, product, vendor, source, or time signals.