Denial of service in activestorage gem for Ruby

Published: 2020-05-26
Risk Medium
Patch available YES
Number of vulnerabilities 1
CVE-ID CVE-2020-8162
Exploitation vector Network
Public exploit N/A
Vulnerable software
Web applications / Modules and components for CMS

Vendor Ruby

Security Bulletin

This security bulletin contains one medium risk vulnerability.

1) Input validation error

EUVDB-ID: #VU28240

Risk: Medium


CVE-ID: CVE-2020-8162

CWE-ID: CWE-20 - Improper Input Validation

Exploit availability: No


The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to insufficient validation of user-supplied input in ActiveStorage's S3 adapter. A remote attacker can control the Content-Length of an S3 direct upload URL without receiving a new signature from the server and perform a denial of service (DoS) attack.


Install updates from vendor's website.

Vulnerable software versions

activestorage: 5.2.0 - 6.0.3 rc1

CPE2.3 External links!topic/rubyonrails-security/PjU3946mreQ

Q & A

Can this vulnerability be exploited remotely?

Is there known malware, which exploits this vulnerability?