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Vulnerabilities

Vulnerability · CVE-2019-5420

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.

Published Mar 27, 2019 · catalog updated Jun 17, 2026 · A remote code execution

Last checked Nov 8, 2026. A connected source was read within the last 7 days.

Check this week

CVE-2019-5420 is not in CISA KEV. FIRST estimates a 89.33% chance of exploitation in the next 30 days. Check whether you run A remote code execution.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (A remote code execution).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
Critical9.8
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
89.33%
Remediation
Version ranges on file
Affected products
cpe debian/debian linux · cpe fedoraproject/fedora · cpe rubyonrails/rails

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe debian/debian linux8.0
  • cpe fedoraproject/fedora30
  • cpe rubyonrails/rails6.0.0
  • cpe rubyonrails/rails< 5.2.2.1

How to fix CVE-2019-5420

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2019-5420 is not in CISA KEV. FIRST estimates a 89.33% chance of exploitation in the next 30 days. Check whether you run A remote code execution.

Which versions are affected?

Compare what you have installed with debian/debian linux 8.0. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-330: Insufficiently Random Values; CWE-77: Command Injection. EPSS 89.33%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

Ruby on Rails security

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Mar 27, 2019 · Monitored products — high

    Detected

    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.

  2. Jun 17, 2026 · Monitored products — high

    Updated

    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.

Sources

  • CVE.orgVulnerability recordCVE-2019-5420

    Official CVE identifier

    cve.org
  • Monitored products — highVendor advisoryCVE-2019-5420

    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.

    nvd.nist.gov
  • Packet Storm SecurityCited referencepacketstormsecurity.com/files/152704/Ruby-On-Rails-DoubleTap-Development-Mode-secret_key_base-Remote-Code-Execution.html

    Packet Storm link already published on the finding.

    packetstormsecurity.com

References

Freshness

Last verified in this catalog Nov 8, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • CVE.orgNov 8, 2026
  • Packet Storm SecurityNov 8, 2026
  • Monitored products — highNov 8, 2026