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 arg…
Vulnerability class: Command Injection (OS Command Injection)
EPSS: 0.008 (52.9th percentile) — read the EPSS interpretation.
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.
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 \
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Mitigation, Vendor Advisory)
- security-advisories@github.com (x_refsource_MISC, Release Notes)
- security-advisories@github.com (x_refsource_MISC, Release Notes)
- security-advisories@github.com (x_refsource_MISC, 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.