---
id: CVE-2026-77611
title: SeaweedFS is a distributed storage system for files and blobs
summary: >-
  SeaweedFS is a distributed storage system for files and blobs. In versions
  prior to 4.40, an authenticated S3 principal with permissions scoped to a
  nested object key can overwrite a different object outside that scope by
  calling PutObje…
severity: high
cvss: 7.1
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:L'
cwe:
  - CWE-863
published: '2026-08-26'
updated: '2026-09-09'
sourceUpdated: '2026-09-09T21:09:13.080'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-77611'
references:
  - url: >-
      https://github.com/seaweedfs/seaweedfs/commit/311bc3a6dfbd042751692bc3de8accc516fcf8c1
    label: security-advisories@github.com
  - url: >-
      https://github.com/seaweedfs/seaweedfs/security/advisories/GHSA-9x53-cjpr-m682
    label: security-advisories@github.com
  - url: >-
      https://github.com/seaweedfs/seaweedfs/security/advisories/GHSA-9x53-cjpr-m682
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
tags:
  - nvd
epss: 0.00221
epssPercentile: 0.12892
ingestedAt: '2026-09-09T21:22:45.557Z'
---

## Overview

SeaweedFS is a distributed storage system for files and blobs. In versions prior to 4.40, an authenticated S3 principal with permissions scoped to a nested object key can overwrite a different object outside that scope by calling PutObjectAcl on the key it is allowed to access. The handler authorizes the request against the requested nested key but then writes the updated entry back to the bucket root rather than the key's actual parent directory, so an ACL change on allowed/protected.txt is instead applied to protected.txt at the bucket root. Because the update carries the full entry rather than only ACL metadata, an existing target object is overwritten with the content, metadata, owner information, and ACL of the scoped object, bypassing the object-level action scoping configured through the static S3 identity file. This issue is fixed in version 4.40.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.