CVE-2019-5420

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.8 under NVD CVSS v3. EPSS exploit probability: 89% (99th percentile of EPSS-scored CVEs). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
Weaponized
9.8EG
EchelonGraph verdictPatch this weekExploitation is likely or a public exploit exists.
  • High exploitation likelihood — EPSS 89%
  • Public exploit code is available (Metasploit, Exploit-DB (verified), epss top5pct, epss high, public exploit)
CISA-KEV: Not listedEPSS PROB: 89%CVSS: 9.8Exploit: Metasploit · Exploit-DB (verified) · epss top5pct · epss high · public exploitExposed services: Not assessed

A fix is available — apply it.

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 v3
9.8
EG Score
9.8CRITICALmedium confidence
EG Risk
84
EG Risk 84/100CISA SSVC

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity98% × 45%
Exploitation89% × 40%
Automatability30% × 15%
CISA SSVC: Track at low, Track* at medium and Attend at high mission impact.
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
89%
EPSS %ILE
99th
KEV
Not listed

CISA SSVCTrack at low, Track* at medium and Attend at high mission impact.

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation public PoC (EG-KEV: weaponized) · Automatable unknown (not published for this CVE) · Technical impact total (CVSS ≥ 9.0). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

March 27, 2019

Last Modified

November 21, 2024

Advisory Details (4)

Auto-updated Oct 5, 2026
🔬 Proof of concept available. Patch available.
generic🟡 PoC Available

Ruby On Rails - DoubleTap Development Mode secret_key_base Remote Code Execution (Metasploit) - Linux remote Exploit

https://www.exploit-db.com/exploits/46785/
generic

[SECURITY] Fedora 30 Update: rubygem-activemodel-5.2.3-2.fc30 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/Y43636TH4D6T46IC6N2RQVJTRFJAAYGA/
generic

Redirecting to Google Groups

https://groups.google.com/forum/#%21topic/rubyonrails-security/IsQKvDqZdKw
generic

Packet Storm

http://packetstormsecurity.com/files/152704/Ruby-On-Rails-DoubleTap-Development-Mode-secret_key_base-Remote-Code-Execution.html

Affected Packages

(5 across 5 ecosystems)
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
rails—
  • every version up to 2:5.2.2.1+dfsg-1: fixed in 2:5.2.2.1+dfsg-1
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
rails—
  • every version up to 2:5.2.2.1+dfsg-1: fixed in 2:5.2.2.1+dfsg-1
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
rails—
  • every version up to 2:5.2.2.1+dfsg-1: fixed in 2:5.2.2.1+dfsg-1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
rails—
  • every version up to 2:5.2.2.1+dfsg-1: fixed in 2:5.2.2.1+dfsg-1
—
RubyGems(1)
PackageVulnerable rangeFix by version rangeDependents
railties5.2.0 ... 5.2.2.rc1 (6 versions)
  • 5.2.0 up to 5.2.2.1: fixed in 5.2.2.1
—

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 2× in last 7d / 12× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-10-07 23:43 UTCEPSS rescore
  2. 2026-10-03 14:22 UTCEPSS rescore
  3. 2026-09-30 10:25 UTCEG score recompute
  4. 2026-09-28 13:46 UTCEPSS rescore
  5. 2026-09-28 11:02 UTCOSV refresh
  6. 2026-09-26 15:54 UTCEPSS rescore
  7. 2026-09-24 13:59 UTCEPSS rescore
  8. 2026-09-22 14:43 UTCEPSS rescore
  9. 2026-09-21 20:28 UTCEPSS rescore
  10. 2026-09-18 19:23 UTCEPSS rescore
  11. 2026-09-16 14:04 UTCEPSS rescore
  12. 2026-09-11 14:48 UTCEPSS rescore
  13. 2026-09-08 14:34 UTCOSV refresh
  14. 2026-09-06 13:44 UTCEPSS rescore
  15. 2026-09-05 15:24 UTCEPSS rescore
  16. 2026-08-26 14:42 UTCEPSS rescore
  17. 2026-08-22 00:41 UTCOSV refresh
  18. 2026-08-19 17:00 UTCEPSS rescore
  19. 2026-08-12 13:47 UTCEPSS rescore
  20. 2026-08-06 05:51 UTCOSV refresh
  21. 2026-08-02 02:23 UTCEPSS rescore
  22. 2026-07-26 14:51 UTCEPSS rescore
  23. 2026-07-24 14:14 UTCEPSS rescore
  24. 2026-07-23 01:45 UTCEG score recompute
  25. 2026-07-22 22:27 UTCEG score recompute
Show 34 more
  1. 2026-07-22 14:05 UTCEPSS rescore
  2. 2026-07-20 19:32 UTCOSV refresh
  3. 2026-07-15 16:55 UTCEPSS rescore
  4. 2026-07-07 13:43 UTCEPSS rescore
  5. 2026-07-06 16:25 UTCEPSS rescore
  6. 2026-07-06 16:25 UTCEPSS rescore
  7. 2026-07-04 06:28 UTCEPSS rescore
  8. 2026-07-03 14:56 UTCOSV refresh
  9. 2026-06-24 14:03 UTCEPSS rescore
  10. 2026-06-24 14:03 UTCEPSS rescore
  11. 2026-06-23 21:31 UTCEPSS rescore
  12. 2026-06-23 21:31 UTCEPSS rescore
  13. 2026-06-16 17:50 UTCEPSS rescore
  14. 2026-06-15 17:46 UTCEPSS rescore
  15. 2026-06-15 04:43 UTCOSV refresh
  16. 2026-06-12 23:09 UTCEPSS rescore
  17. 2026-06-12 23:09 UTCEPSS rescore
  18. 2026-06-11 13:58 UTCEPSS rescore
  19. 2026-06-10 13:19 UTCEPSS rescore
  20. 2026-06-05 06:08 UTCEPSS rescore
  21. 2026-06-04 13:10 UTCEPSS rescore
  22. 2026-06-04 13:10 UTCEPSS rescore
  23. 2026-06-02 20:11 UTCEPSS rescore
  24. 2026-06-02 20:11 UTCEPSS rescore
  25. 2026-06-01 13:50 UTCEPSS rescore
  26. 2026-06-01 13:50 UTCEPSS rescore
  27. 2026-05-31 22:29 UTCEPSS rescore
  28. 2026-05-31 22:29 UTCEPSS rescore
  29. 2026-05-29 13:42 UTCEPSS rescore
  30. 2026-05-27 21:22 UTCEG score recompute
  31. 2026-05-26 07:17 UTCEPSS rescore
  32. 2026-05-26 07:17 UTCEPSS rescore
  33. 2026-05-26 07:17 UTCEPSS rescore
  34. 2026-05-24 16:47 UTCEPSS rescore

Publicly available exploits

(6 references)

Working exploit code is in the public domain (1 Metasploit module) (4 GitHub PoCs) (1 Exploit-DB entry). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • Exploit-DBEDB-46785✓ verified
    First seen May 2, 2019

    Ruby On Rails - DoubleTap Development Mode secret_key_base Remote Code Execution (Metasploit)

    Open source ↗
  • Metasploitexploit/multi/http/rails_double_tap✓ verified
    First seen Mar 13, 2019

    Ruby On Rails DoubleTap Development Mode secret_key_base Vulnerability

    Open source ↗
  • GitHub PoClaffray/ruby-RCE-CVE-2019-5420-
    First seen Jul 2, 2022

    Ruby反序列化命令执行漏洞（CVE-2019-5420）-vulfocus通关版

    Open source ↗
  • GitHub PoCj4k0m/CVE-2019-5420
    First seen Sep 6, 2021

    A vulnerability can allow an attacker to guess the automatically generated development mode secret token.

    Open source ↗
  • GitHub PoCscumdestroy/CVE-2019-5420.rb
    First seen May 11, 2021

    POC Exploit written in Ruby

    Open source ↗
  • GitHub PoCknqyf263/CVE-2019-5420
    First seen Mar 21, 2019

    CVE-2019-5420 (Ruby on Rails)

    Open source ↗

Related CVEs(same product + same CWE)

Frequently asked(5)

What is CVE-2019-5420?
CVE-2019-5420 is a critical vulnerability published on March 27, 2019. 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.
When was CVE-2019-5420 disclosed?
CVE-2019-5420 was first published on March 27, 2019, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2019-5420 actively exploited?
CVE-2019-5420 is not currently on CISA's Known Exploited Vulnerabilities catalog. EchelonGraph's EG-KEV model classifies it as weaponized: a functional public exploit exists. FIRST EPSS estimates a 89% probability of exploitation in the next 30 days (99th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2019-5420?
CVE-2019-5420 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2019-5420?
A fix for CVE-2019-5420 is available: update to the fixed version the vendor names in its advisory.

Dependency Blast Radius

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