Remote code execution via user-provided local names in ActionView

published 2020-07-02 6 y ago modified 2026-06-17 4 mo ago also BIT-rails-2020-8163 , EUVD-2020-0551 , GHSA-cr3x-7m39-c6jq

cvss: 8.8; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 82.5%; EPSS 82.5% chance of exploitation in 30 days, percentile 99.6%
public exploits: 1; Exploit-DB, plus a Nuclei check

The is a code injection vulnerability in versions of Rails prior to 5.0.1 that wouldallow an attacker who controlled the `locals` argument of a `render` call to perform a RCE.

Patch / fix

fixed in 3 distros 2 links 1

rubygems actionview 4.2.11.3
bitnami rails 5.0.1
rubyonrails rails 5.0.1

debian suse

rails Debian 14, Debian 13, Debian 12 2:5.2.0+dfsg-2

debian advisories DEBIAN-CVE-2020-8163

rubygem-actionview-4_2 OpenStack Cloud Crowbar 9, OpenStack Cloud Crowbar 8, OpenStack Cloud 7 +1 more 4.2.9-9.9.1
rubygem-activesupport-4_2 OpenStack Cloud Crowbar 9, OpenStack Cloud Crowbar 8, OpenStack Cloud 7 +1 more 4.2.9-7.6.1

suse advisories SUSE-SU-2020:2140-1

groups.google.com/g/rubyonrails-security/c/hWuKcHyoKh0 advisory

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2020-8163 updated 2025-11-21 cvss 8.8

rubygem-rails: potential remote code execution of user-provided local names

Red Hat CloudForms Management Engine 5 cfme-gemset, cfme-amazon-smartstate Red Hat Satellite 6 tfm-ror52-rubygem-rails
not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Timeline

2020-07-02 Published
2020-07-26 First public exploit (EDB-48716)

Exploit prediction

82.47% chance of exploitation in the next 30 days, higher than 99.6% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

EDB-48716 Rails 5.0.1 - Remote Code Execution webapps, 2020-07-26
Nuclei template Ruby on Rails <5.0.1 - Remote Code Execution nuclei detection template
packetstormsecurity.com http://packetstormsecurity.com/files/158604/Ruby-On-Rails-5.0.1-Remote-Code-Execution.html referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
GitHub	3.1	8.8	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD	3.1	8.8	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD	2.0	6.5	AV:N/AC:L/Au:S/C:P/I:P/A:P
OSV	3.1	8.8	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem	package	affected	fixed in
rubygems	actionview	<4.2.11.3	4.2.11.3
bitnami	rails	<5.0.1	5.0.1

Affected products

n/a https://github.com/rails/rails

Classification

Weakness

CWE-94 Improper Control of Generation of Code

Technology feeds

Ruby on Rails rss critical rss

References

groups.google.com /g/rubyonrails-security/c/hWuKcHyoKh0
web, mailing-list, patch, third-party-advisory
packetstormsecurity.com /files/158604/Ruby-On-Rails-5.0.1-Remote-Code-Execution.html
web, exploit, third-party-advisory, vdb-entry
hackerone.com /reports/304805
web, permissions-required, third-party-advisory
lists.debian.org /debian-lts-announce/2020/07/msg00013.html
mailing-list, web, third-party-advisory
nvd.nist.gov /vuln/detail/CVE-2020-8163
advisory, web
github.com /rubysec/ruby-advisory-db/blob/master/gems/actionview/CVE-2020-8163.yml
web
groups.google.com /forum/#!topic/rubyonrails-security/hWuKcHyoKh0
web

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary