# CVE-2019-18409: Ruby_parser-legacy Incorrect Permission Assignment for Critical Resource

> Local attackers can escalate privileges by injecting malicious code into world-writable files within the ruby_parser-legacy gem.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 24 Oct 2019
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-hhwc-8g49-j8jx

## What is CVE-2019-18409?

CVE-2019-18409 is a high-severity vulnerability in n/a, published on 24 Oct 2019. It can only be exploited from the same machine or local network, with no action from the victim.

### Official 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.

Weakness: CWE-732 (Incorrect Permission Assignment for Critical Resource)

## Which versions are affected by CVE-2019-18409?

2 open source packages ship an affected version, including ruby_parser-legacy. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `ruby_parser-legacy` | RubyGems | All versions to 1.0.0 | None |
| `ruby_parser-legacy` | RubyGems | All versions to 1.0.0 | None |

Products: Zenspider Ruby Parser-Legacy.

## How do I fix CVE-2019-18409?

No fix has been published for CVE-2019-18409 yet. Limit exposure of the affected software until one is available.

## Is CVE-2019-18409 being exploited?

There is no known exploitation of CVE-2019-18409 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2019-18409 and fix it if it is affected.

What it is: CVE-2019-18409 is a high-severity vulnerability in n/a, published on 24 Oct 2019. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2019-18409 in the wild and no public exploit code.

Affected packages and fixed versions:
- ruby_parser-legacy (RubyGems): affected all versions up to 1.0.0; no fix listed
- ruby_parser-legacy (RubyGems): affected all versions up to 1.0.0; no fix listed

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2019-18409/ (Markdown: https://insights.sbomify.com/CVE-2019-18409/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-18409
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-18409
- OSV: https://osv.dev/vulnerability/CVE-2019-18409

---
From sbomify Insights: https://insights.sbomify.com/CVE-2019-18409/
Summaries are generated and may contain mistakes; the official description above is the record.