CVE-2019-18409

Name: CVE-2019-18409
Creator: NVD / NIST
Published: 2019-10-24T14:15:11.583+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.8/10EPSS 0.33%

Last modified Jun 17, 2026

CVE-2019-18409 is a high-severity vulnerability rated 7.8/10 on the CVSS scale. The ruby_parser-legacy (aka legacy) gem 1.0.0 for Ruby allows local privilege escalation because of world-writable files. For example, if the brakeman gem (which has a legacy dependency) 4.5.0 through 4.7.0 is used, a local user can insert malicious code into the ruby_parser-legacy-1.0.0/lib/ruby_parser/legacy/ruby_parser.rb file.. EPSS estimates a 0.33% chance of exploitation in the next 30 days.

Description

The ruby_parser-legacy (aka legacy) gem 1.0.0 for Ruby allows local privilege escalation because of world-writable files. For example, if the brakeman gem (which has a legacy dependency) 4.5.0 through 4.7.0 is used, a local user can insert malicious code into the ruby_parser-legacy-1.0.0/lib/ruby_parser/legacy/ruby_parser.rb file.

Metrics

CVSS 3.1

7.8/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

0.33%

24.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-732

Affected Software

Vendor	Product	Versions
Zenspider	Ruby Parser-Legacy	1.0.0

References

https://github.com/zenspider/ruby_parser-legacy/issues/1Exploit, Issue Tracking, Third Party Advisory
https://github.com/zenspider/ruby_parser-legacy/issues/1Exploit, Issue Tracking, Third Party Advisory

Timeline

Published: Oct 24, 2019
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2019-18409?

How severe is CVE-2019-18409?

CVE-2019-18409 has a CVSS score of 7.8/10 (HIGH severity). The EPSS model estimates a 0.33% probability of exploitation in the next 30 days.

How do I fix CVE-2019-18409?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2019-18409?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST