Auth bypass in Rustfs
CVE-2026-27607
RustFS is a distributed object storage system built in Rust. In versions 1.0.0-alpha.56 through 1.0.0-alpha.82, RustFS does not validate policy conditions in presigned POST uploads (PostObject), allowing attackers to bypass content-length-range, starts-with, and Content-Type constraints. This enables unauthorized file uploads exceeding size limits, uploads to arbitrary object keys, and content-type spoofing, potentially leading to storage exhaustion, unauthorized data access, and security bypasses. Version 1.0.0-alpha.83 fixes the issue.
Vulnerability class: Drupalgeddon 2 (CVE-2018-7600)
EPSS: 0.003 (18.3th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 8.1 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H.
Affected products
- Rustfs — versions 1.0.0, >= 1.0.0-alpha.56, < 1.0.0-alpha.83
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-27607?
- CVE-2026-27607 is a high-severity vulnerability in Rustfs, classified under Improper Input Validation. CVSS score: 8.1/10. Published 2026-02-25.
- How severe is CVE-2026-27607?
- High severity. CVSS v3 base score is 8.1 out of 10.