CVE-2020-8166

Name: CVE-2020-8166
Creator: NVD / NIST
Published: 2020-07-02T19:15:12.513+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 4.3/10EPSS 1.67%

Last modified Jun 17, 2026

CVE-2020-8166 is a medium-severity vulnerability rated 4.3/10 on the CVSS scale. A CSRF forgery vulnerability exists in rails < 5.2.5, rails < 6.0.4 that makes it possible for an attacker to, given a global CSRF token such as the one present in the authenticity_token meta tag, forge a per-form CSRF token.. EPSS estimates a 1.67% chance of exploitation in the next 30 days.

Description

A CSRF forgery vulnerability exists in rails < 5.2.5, rails < 6.0.4 that makes it possible for an attacker to, given a global CSRF token such as the one present in the authenticity_token meta tag, forge a per-form CSRF token.

Metrics

CVSS 3.1

4.3/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N

EPSS Probability

1.67%

73.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Rubyonrails	Rails	< 5.2.4.3
Rubyonrails	Rails	>= 6.0.0, < 6.0.3.1
Debian	Debian Linux	10.0

References

https://groups.google.com/g/rubyonrails-security/c/NOjKiGeXUgwMailing List, Patch, Third Party Advisory
https://hackerone.com/reports/732415Exploit, Third Party Advisory
https://www.debian.org/security/2020/dsa-4766Third Party Advisory
https://groups.google.com/g/rubyonrails-security/c/NOjKiGeXUgwMailing List, Patch, Third Party Advisory
https://hackerone.com/reports/732415Exploit, Third Party Advisory
https://www.debian.org/security/2020/dsa-4766Third Party Advisory
https://hackerone.com/reports/732415Exploit, Third Party Advisory

Timeline

Published: Jul 2, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-8166?

How severe is CVE-2020-8166?

CVE-2020-8166 has a CVSS score of 4.3/10 (MEDIUM severity). The EPSS model estimates a 1.67% probability of exploitation in the next 30 days.

How do I fix CVE-2020-8166?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2020-8166?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST