CVE-2019-5420

highpriority · act · 80OT risk · criticalEPSS 0.893 · 100 %ileexploit · weaponizedDEEURUUS

grimoire priorityP1 · Urgent

Exploitable?

Public exploit

14 exploits · weaponized

Likely / severe?

89.3% (100th) EPSS

CVSS 7.5 · high

Is it mine?

16 products

Check your exposure

Who says so?

6 sources

cnnvd · enisa_euvd · fstec_bdu · cert_bund

EPSS · scored 2026-10-22

A remote code execution vulnerability in development mode Rails <5.2.2.1, <6.0.0.beta3 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.

cvss

Technical severity, 0–10. One row per scoring source.

9.8

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · high–critical · 7.5–9.8

v2.07.5highAV:N/AC:L/Au:N/C:P/I:P/A:Pprimary · NVD / NIST USexploitability 10 · impact 6.4

v3.19.8criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hprimary · NVD / NIST USexploitability 3.9 · impact 5.9

v3.09.8criticalCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hsecondary · OSV

v3.18.1highAV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:Hsecondary · FSTEC (BDU) RU

v3.19.8criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:Hsecondary · CVSS-BT (t0sche)

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-330USprimaryCWE-330USCWE-338USCWE-77USCWE-77US

exploits (14)

Public proof-of-concept and weaponised exploit code.

exploit/multi/http/rails_double_tapRuby On Rails DoubleTap Development Mode secret_key_base Vulnerabilityweaponized · metasploit
EDB-46785Ruby On Rails - DoubleTap Development Mode secret_key_base Remote Code Execution (Metasploit)functional · exploit_db
AnasTaoutaou/CVE-2019-5420AnasTaoutaou/CVE-2019-5420PoC · poc_in_github
Eremiel/CVE-2019-5420Eremiel/CVE-2019-5420PoC · poc_in_github
PenTestical/CVE-2019-5420 Exploit in Rails Development Mode. With some knowledge of a target application it is possible for 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.PoC · poc_in_github
WildWestCyberSecurity/cve-2019-5420-POCcve-2019-5420 POC simple ruby scriptPoC · poc_in_github

affected products (16)

Products and version ranges known to be affected.

Open Source Ruby on Rails <5.2.2.1all versionscert_bundDE
Open Source Ruby on Rails <6.0.0.beta3all versionscert_bundDE
Red Hat Enterprise Linuxall versionscert_bundDEcpe:/o:redhat:enterprise_linux:-
SUSE Linuxall versionscert_bundDEcpe:/o:suse:suse_linux:-
Ubuntu Linuxall versionscert_bundDEcpe:/o:canonical:ubuntu_linux:-
Open Source Ruby on Rails< 5.2.2.1cert_bundDE
Open Source Ruby on Rails< 6.0.0.beta3cert_bundDE
rails https://github.com/rails/rails≤ 6.0.0.beta3enisa_euvdEU
rails https://github.com/rails/rails≤ 5.2.2.1enisa_euvdEU
Rails Core Team Ruby on Rails5.2.0 → 5.2.2.1fstec_bduRU
Rails Core Team Ruby on Rails6.0.0 → 6.0.0.beta3fstec_bduRU
debian debian linux= 8.0nvdUScpe:2.3:o:debian:debian_linux:*:*:*:*:*:*:*:*
fedoraproject fedora= 30nvdUScpe:2.3:o:fedoraproject:fedora:*:*:*:*:*:*:*:*
rubyonrails rails< 5.2.2.1nvdUScpe:2.3:a:rubyonrails:rails:*:*:*:*:*:*:*:*
rubyonrails rails= 6.0.0nvdUScpe:2.3:a:rubyonrails:rails:*:*:*:*:*:*:*:*
RubyGems railties5.2.0 → 5.2.2.1osvUSpkg:gem/railties

advisories (2)

Vendor and ecosystem advisories describing this.

WID-SEC-W-2025-1467Ruby on Rails: Mehrere SchwachstellenDeutsch2019-03-13csaf · cert_bundDE
Ein Angreifer kann mehrere Schwachstellen in Ruby on Rails ausnutzen, um Informationen offenzulegen, einen Denial of Service Zustand hervorzurufen oder beliebigen Programmcode auszuführen.
GHSA-m42h-mh85-4qgcUse of Insufficiently Random Values in Railties Allows Remote Code Execution2019-03-13ghsa · osvUS
# Possible Remote Code Execution Exploit in Rails Development Mode Impact ------ With some knowledge of a target application it is possible for 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. All users running an affected release should either upgrade or use one of the workarounds immediately. Releases -------- The 6.0.0.beta3 and 5.2.2.1 releases are available at the normal locations. Workarounds ----------- This issue can be mitigated by specifying a secret key in development mode. In "config/environments/development.rb" add this: ``` config.secret_key_base = SecureRandom.hex(64) ``` Please note that only the 5.2.x, 5.1.x, 5.0.x, and 4.2.x series are supported at present. Users of earlier unsupported releases are advised to upgrade as soon as possible as we cannot guarantee the continued availability of security fixes for unsupported releases. Credits ------- Thanks to ooooooo_q

also known as (4)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd fstec_bdu cert_bund nvd osv NVD CVE.org MITRE

published 2019-03-27modified 2026-10-14

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Related entries.

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+563 more

references (26)

External citations — patches, advisories, analysis.

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