RCE in Ruby Net-Imap
CVE-2026-42258
Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. Prior to versions 0.4.24, 0.5.14, and 0.6.4, symbol arguments to commands are vulnerable to a CRLF Injection / IMAP Command injection via Symbol arguments passed to IMAP commands. This issue has been patched in versions 0.4.24, 0.5.14, and 0.6.4.
Vulnerability class: Command Injection (OS Command Injection)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:L.
EPSS exploit prediction
EPSS: 0.013 (69.0th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 69th percentile — 69.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.008 · newest: 0.013 · change: +0.005
Affected products
- Ruby Net-Imap — versions < 0.4.24, >= 0.5.0, < 0.5.14, >= 0.6.0, < 0.6.4
- Ruby-Lang Net\ — versions \
- Ruby-Lang Net\:\:imap
Weakness classification (CWE)
References
- https://github.com/ruby/net-imap/security/advisories/GHSA-75xq-5h9v-w6px (Mitigation, Vendor Advisory)
- https://github.com/ruby/net-imap/releases/tag/v0.4.24 (Release Notes)
- https://github.com/ruby/net-imap/releases/tag/v0.5.14 (Release Notes)
- https://github.com/ruby/net-imap/releases/tag/v0.6.4 (Release Notes)
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
Frequently asked questions
- What is CVE-2026-42258?
- CVE-2026-42258 is a medium-severity vulnerability in Ruby Net-Imap, classified under Command Injection. CVSS score: 5.3/10. Published 2026-05-09.
- How severe is CVE-2026-42258?
- Medium severity. CVSS v3 base score is 5.3 out of 10.