How severe is CVE-2019-18409?

CVE-2019-18409 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2019-18409 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (25th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2019-18409?

CVE-2019-18409 affects Zenspider Ruby Parser-legacy. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2019-18409?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2019-18409 published?

CVE-2019-18409 was published on 2019-10-24 and last updated on 2026-06-17.

CVE-2019-18409

CVE-2019-18409 is a high-severity vulnerability in Zenspider Ruby Parser-legacy with a CVSS 3.x base score of 7.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-732.

Key facts

Severity: High (CVSS 3.x base score 7.8)
CVSS v2: 4.6
EPSS exploit prediction: 0% (25th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-732
Affected product: Zenspider Ruby Parser-legacy
Published: 2019-10-24
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2019-18409?: 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.
How severe is CVE-2019-18409?: CVE-2019-18409 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2019-18409 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (25th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2019-18409?: CVE-2019-18409 affects Zenspider Ruby Parser-legacy. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2019-18409?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2019-18409 published?: CVE-2019-18409 was published on 2019-10-24 and last updated on 2026-06-17.

References

https://github.com/zenspider/ruby_parser-legacy/issues/1

Affected products (1)

cpe:2.3:a:zenspider:ruby_parser-legacy:1.0.0:*:*:*:*:ruby:*:*

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