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Vulnerability details: VCID-zydu-j9dg-fqdb
Vulnerability ID VCID-zydu-j9dg-fqdb
Aliases CVE-2019-5420
GHSA-m42h-mh85-4qgc
Summary Improper Input Validation A remote code execution vulnerability in development mode Rails can allow an attacker to guess the automatically generated development mode secret token. This secret token can be used in combination with other Rails internals to escalate to a remote code execution exploit.
Status Published
Exploitability 2.0
Weighted Severity 9.0
Risk 10.0
Affected and Fixed Packages Package Details
Weaknesses (6)
CWE-1035 OWASP Top Ten 2017 Category A9 - Using Components with Known Vulnerabilities
CWE-20 Improper Input Validation
CWE-937 OWASP Top Ten 2013 Category A9 - Using Components with Known Vulnerabilities
CWE-330 Use of Insufficiently Random Values
CWE-77 Improper Neutralization of Special Elements used in a Command ('Command Injection')
CWE-338 Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)
System Score Found at
cvssv3.1 9.8 http://packetstormsecurity.com/files/152704/Ruby-On-Rails-DoubleTap-Development-Mode-secret_key_base-Remote-Code-Execution.html
generic_textual CRITICAL http://packetstormsecurity.com/files/152704/Ruby-On-Rails-DoubleTap-Development-Mode-secret_key_base-Remote-Code-Execution.html
cvssv3 8.1 https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2019-5420.json
epss 0.93745 https://api.first.org/data/v1/epss?cve=CVE-2019-5420
epss 0.93745 https://api.first.org/data/v1/epss?cve=CVE-2019-5420
epss 0.93745 https://api.first.org/data/v1/epss?cve=CVE-2019-5420
cvssv3.1 8.1 https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
cvssv3.1_qr CRITICAL https://github.com/advisories/GHSA-m42h-mh85-4qgc
cvssv3.1 9.8 https://github.com/rubysec/ruby-advisory-db/blob/master/gems/railties/CVE-2019-5420.yml
generic_textual CRITICAL https://github.com/rubysec/ruby-advisory-db/blob/master/gems/railties/CVE-2019-5420.yml
cvssv3 9.8 https://groups.google.com/forum/#!topic/rubyonrails-security/IsQKvDqZdKw
cvssv3.1 9.8 https://groups.google.com/forum/#!topic/rubyonrails-security/IsQKvDqZdKw
generic_textual CRITICAL https://groups.google.com/forum/#!topic/rubyonrails-security/IsQKvDqZdKw
cvssv3.1 9.8 https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/Y43636TH4D6T46IC6N2RQVJTRFJAAYGA
generic_textual CRITICAL https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/Y43636TH4D6T46IC6N2RQVJTRFJAAYGA
cvssv2 7.5 https://nvd.nist.gov/vuln/detail/CVE-2019-5420
cvssv3.1 9.8 https://nvd.nist.gov/vuln/detail/CVE-2019-5420
cvssv3.1 9.8 https://nvd.nist.gov/vuln/detail/CVE-2019-5420
generic_textual CRITICAL https://nvd.nist.gov/vuln/detail/CVE-2019-5420
cvssv3.1 9.8 https://weblog.rubyonrails.org/2019/3/13/Rails-4-2-5-1-5-1-6-2-have-been-released
generic_textual CRITICAL https://weblog.rubyonrails.org/2019/3/13/Rails-4-2-5-1-5-1-6-2-have-been-released
cvssv3.1 9.8 https://www.exploit-db.com/exploits/46785
generic_textual CRITICAL https://www.exploit-db.com/exploits/46785
Reference id Reference type URL
http://packetstormsecurity.com/files/152704/Ruby-On-Rails-DoubleTap-Development-Mode-secret_key_base-Remote-Code-Execution.html
https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2019-5420.json
https://api.first.org/data/v1/epss?cve=CVE-2019-5420
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-5420
https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
https://github.com/rubysec/ruby-advisory-db/blob/master/gems/railties/CVE-2019-5420.yml
https://groups.google.com/forum/#%21topic/rubyonrails-security/IsQKvDqZdKw
https://groups.google.com/forum/#!topic/rubyonrails-security/IsQKvDqZdKw
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/Y43636TH4D6T46IC6N2RQVJTRFJAAYGA/
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/Y43636TH4D6T46IC6N2RQVJTRFJAAYGA
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/Y43636TH4D6T46IC6N2RQVJTRFJAAYGA/
https://weblog.rubyonrails.org/2019/3/13/Rails-4-2-5-1-5-1-6-2-have-been-released
https://weblog.rubyonrails.org/2019/3/13/Rails-4-2-5-1-5-1-6-2-have-been-released/
https://www.exploit-db.com/exploits/46785
https://www.exploit-db.com/exploits/46785/
1689154 https://bugzilla.redhat.com/show_bug.cgi?id=1689154
924521 https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=924521
cpe:2.3:a:rubyonrails:rails:*:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:rubyonrails:rails:*:*:*:*:*:*:*:*
cpe:2.3:a:rubyonrails:rails:6.0.0:beta1:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:rubyonrails:rails:6.0.0:beta1:*:*:*:*:*:*
cpe:2.3:a:rubyonrails:rails:6.0.0:beta2:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:rubyonrails:rails:6.0.0:beta2:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:30:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:o:fedoraproject:fedora:30:*:*:*:*:*:*:*
CVE-2019-5420 Exploit https://gitlab.com/exploit-database/exploitdb/-/blob/main/exploits/linux/remote/46785.rb
CVE-2019-5420 https://nvd.nist.gov/vuln/detail/CVE-2019-5420
CVE-2019-5420 Exploit https://raw.githubusercontent.com/rapid7/metasploit-framework/master/modules/exploits/multi/http/rails_double_tap.rb
GHSA-m42h-mh85-4qgc https://github.com/advisories/GHSA-m42h-mh85-4qgc
Data source Exploit-DB
Date added May 2, 2019
Description Ruby On Rails - DoubleTap Development Mode secret_key_base Remote Code Execution (Metasploit)
Ransomware campaign use Known
Source publication date May 2, 2019
Exploit type remote
Platform linux
Source update date May 2, 2019
Source URL https://raw.githubusercontent.com/rapid7/metasploit-framework/master/modules/exploits/multi/http/rails_double_tap.rb
Data source Metasploit
Description This module exploits a vulnerability in Ruby on Rails. In development mode, a Rails application would use its name as the secret_key_base, and can be easily extracted by visiting an invalid resource for a path. As a result, this allows a remote user to create and deliver a signed serialized payload, load it by the application, and gain remote code execution.
Note 
AKA:
  - doubletap
Stability:
  - crash-safe
SideEffects:
  - ioc-in-logs
Reliability:
  - unknown-reliability
Ransomware campaign use Unknown
Source publication date March 13, 2019
Platform Linux
Source URL https://github.com/rapid7/metasploit-framework/tree/master/modules/exploits/multi/http/rails_double_tap.rb
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Found at http://packetstormsecurity.com/files/152704/Ruby-On-Rails-DoubleTap-Development-Mode-secret_key_base-Remote-Code-Execution.html
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H Found at https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2019-5420.json
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H Found at https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Found at https://github.com/rubysec/ruby-advisory-db/blob/master/gems/railties/CVE-2019-5420.yml
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Found at https://groups.google.com/forum/#!topic/rubyonrails-security/IsQKvDqZdKw
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Found at https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/Y43636TH4D6T46IC6N2RQVJTRFJAAYGA
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: AV:N/AC:L/Au:N/C:P/I:P/A:P Found at https://nvd.nist.gov/vuln/detail/CVE-2019-5420
Exploitability (E) Access Vector (AV) Access Complexity (AC) Authentication (Au) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

high

functional

unproven

proof_of_concept

not_defined

local

adjacent_network

network

high

medium

low

multiple

single

none

none

partial

complete

none

partial

complete

none

partial

complete
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Found at https://nvd.nist.gov/vuln/detail/CVE-2019-5420
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Found at https://nvd.nist.gov/vuln/detail/CVE-2019-5420
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Found at https://weblog.rubyonrails.org/2019/3/13/Rails-4-2-5-1-5-1-6-2-have-been-released
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Found at https://www.exploit-db.com/exploits/46785
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Exploit Prediction Scoring System (EPSS)
Percentile 0.9985
EPSS Score 0.93745
Published At April 1, 2026, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2026-04-01T12:48:22.732909+00:00 GitLab Importer Import https://gitlab.com/gitlab-org/advisories-community/-/blob/main/gem/rails/CVE-2019-5420.yml 38.0.0