---
id: "CVE-2026-122267"
page: "https://infrastack.ai/live/CVE-2026-122267"
kind: "vulnerability"
aliases: ["CVE-2026-122267"]
title: "MinIO: unsigned x-amz headers let presigned URLs read across buckets"
severity: "high"
cvss: 8.8
epss: null
exploited: false
status: "open"
category: "infrastructure"
products: []
ecosystems: []
tags: ["infrastructure", "minio", "s3-compatible-storage", "self-hosted"]
not_affected_if: ["fixed-release", "no-presigned-urls"]
published_at: "2026-11-05T22:17:55+00:00"
first_seen_at: "2026-11-05T22:46:06+00:00"
updated_at: "2026-11-05T22:46:36+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-122267", "first_seen_at": "2026-11-05T22:46:06+00:00"}]
exploit_sources: []
---

# MinIO: unsigned x-amz headers let presigned URLs read across buckets

Link for people: https://infrastack.ai/live/CVE-2026-122267 (this .md is for agents)

MinIO's Signature V4 check, before RELEASE.2026-09-22T19-25-18Z, accepts unsigned x-amz-* headers. An attacker holding a presigned PUT URL can escalate it into a read from another bucket.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the running MinIO release, for example with `minio --version`, and compare it to `RELEASE.2026-09-22T19-25-18Z`.
- Look for presigned URL use in applications that talk to MinIO.

## Fix

- Move to MinIO `RELEASE.2026-09-22T19-25-18Z` or later.

## Timeline

- 2026-11-05T22:46:06+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-122267

## Documents

- [advisory] Vendor advisory: github.com https://github.com/chainguard-forks/minio/security/advisories/GHSA-48rv-pgqh-mhjg

## From the sources

MinIO Signature V4 verification before RELEASE.2026-09-22T19-25-18Z accepts unsigned x-amz-* headers, letting a presigned PUT URL be escalated into a cross-bucket read.

---

_Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai_