CVE-2026-27607

high-risk

Published 2026-02-25

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.

Do I need to act?

0.10% chance of exploitation

EPSS score — low exploit probability

Not on CISA KEV list

No confirmed active exploitation reported to CISA

Patch status unknown

Check vendor advisories for fix availability and mitigation guidance

CVSS 8.1/10 High

NETWORK / LOW complexity

Affected Products (20)

Rustfs

Affected Vendors

Rustfs

References (1)

Vendor Advisory https://github.com/rustfs/rustfs/security/advisories/GHSA-w5fh-f8xh-5x3p

/ 100

high-risk

Severity 28/34 · Critical

Exploitability 0/34 · Minimal

Exposure 22/34 · High