CVE-2020-8162
mediumpriority · track · 41EPSS 0.030 · 87 %ileexploit · PoCDEEURUUSEPSS · scored 2026-10-26
A client side enforcement of server side security vulnerability exists in rails < 5.2.4.2 and rails < 6.0.3.1 ActiveStorage's S3 adapter that allows the Content-Length of a direct file upload to be modified by an end user bypassing upload limits.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–critical · 5–9.8
weaknesses
The CWE weakness classes this flaw belongs to.
exploits (1)
Public proof-of-concept and weaponised exploit code.
affected products (13)
Products and version ranges known to be affected.
advisories (2)
Vendor and ecosystem advisories describing this.
- WID-SEC-W-2023-1093Ruby on Rails: Mehrere SchwachstellenDeutsch2020-05-18csaf · cert_bundDE
Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in Ruby on Rails ausnutzen, um Sicherheitsvorkehrungen zu umgehen, Informationen offenzulegen, beliebigen Programmcode auszuführen oder Dateien zu manipulieren.
- GHSA-m42x-37p3-fv5wCircumvention of file size limits in ActiveStorage2020-05-26ghsa · osvUS
There is a vulnerability in ActiveStorage's S3 adapter that allows the Content-Length of a direct file upload to be modified by an end user. Versions Affected: rails < 5.2.4.2, rails < 6.0.3.1 Not affected: Applications that do not use the direct upload functionality of the ActiveStorage S3 adapter. Fixed Versions: rails >= 5.2.4.3, rails >= 6.0.3.1 Impact ------ Utilizing this vulnerability, an attacker can control the Content-Length of an S3 direct upload URL without receiving a new signature from the server. This could be used to bypass controls in place on the server to limit upload size. Workarounds ----------- This is a low-severity security issue. As such, no workaround is necessarily until such time as the application can be upgraded.
also known as (4)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (14)
External citations — patches, advisories, analysis.
- https://groups.google.com/g/rubyonrails-security/c/PjU3946mreQcnnvd
- https://hackerone.com/reports/789579cnnvd
- https://nvd.nist.gov/vuln/detail/CVE-2020-8162cnnvd
- https://vigilance.fr/vulnerability/rails-four-vulnerabilities-33413cnnvd
- https://weblog.rubyonrails.org/2020/5/18/Rails-5-2-4-3-and-6-0-3-1-have-been-released/Patchcnnvd
- https://www.auscert.org.au/bulletins/ESB-2020.1780/cnnvd
- https://www.auscert.org.au/bulletins/ESB-2020.3278/cnnvd
- https://www.debian.org/security/2020/dsa-4766cnnvd
Attackers weaponise vulnerabilities like this against internet-exposed services. See what is exposed on your perimeter with a free passive scan.
Free scan