Is this vulnerability remotely exploitable?

Yes. Any client that can reach the RustFS presigned POST upload endpoint and obtain a valid presigned policy can exploit the missing validation checks remotely over the network.

Does exploitation require authenticated access?

Typically, yes, in the sense that an attacker must obtain or be issued a presigned POST policy through some authenticated or semi-trusted workflow. However, if presigned forms are broadly distributed, leaked, or reused across users, practical access requirements may be low.

What is the safest general fix pattern?

Implement mandatory server-side validation of all presigned POST policy conditions before accepting an upload. The server should enforce size limits, key constraints, and Content-Type rules derived from the policy, and reject any request that violates them, regardless of what the client sends.

Severity:

HIGH RISK

(8.1)

Improper Input Validation in Presigned POST Policy Enforcement (CWE-20) in RustFS Object Storage

CVE-2026-27607

Published:

Feb 24, 2026

Status:

Analyzed

Summary

Affected Context

Exploit Preconditions

Why This Happens

Potential Impact

General Mitigation Guidance

How Teams Detect Issues Like This

Frequently Asked Questions

Source

NDV

Recent Vulnerabilities

CWE-77;CWE-78

HIGH RISK

HIGH

(7.3)

OS Command Injection (CWE-78) in Totolink A7100RU setGameSpeedCfg CGI Handler

Remote Code Execution on the Router

April 6, 2026

CWE-77;CWE-78

HIGH RISK

HIGH

(7.3)

OS Command Injection (CWE-78) in Totolink A7100RU setFirewallType Handler

Remote Code Execution on Router Firmware

April 6, 2026

Vulnerability Type

Category:

Improper Input Validation

CWE:

CWE-20;CWE-863

Impact:

Security Policy Bypass and Unauthorized File Uploads

Severity:

HIGH RISK

(8.1)

CVSS Version:

3.1

Vulnerability Type

Category:

Improper Input Validation

CWE:

CWE-20;CWE-863

Impact:

Security Policy Bypass and Unauthorized File Uploads

Severity:

HIGH RISK

(8.1)

CVSS Version:

3.1

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Ask AI for summary of CodeAnt

Improper Input Validation in Presigned POST Policy Enforcement (CWE-20) in RustFS Object Storage

Summary

Affected Context

Exploit Preconditions

Why This Happens

Potential Impact

General Mitigation Guidance

How Teams Detect Issues Like This

Frequently Asked Questions

Source

Recent Vulnerabilities

HIGH RISK

HIGH

(7.3)

OS Command Injection (CWE-78) in Totolink A7100RU setGameSpeedCfg CGI Handler

HIGH RISK

HIGH

(7.3)

OS Command Injection (CWE-78) in Totolink A7100RU setFirewallType Handler

Vulnerability Type

Vulnerability Type

Vulnerability Type

Catch This CVE While Code Is Being Written

Ship clean & secure code faster

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