CVE-2026-42257
If this string is derived from user-controlled input, it may contain contain CRLF sequences, which an attacker can use to inject arbitrary IMAP commands.
Does this matter?
Lower severity and a low EPSS score (0.43%). Track it; it rarely justifies an emergency change on its own.
Description
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, several Net::IMAP commands accept a raw string argument that is sent to the server without validation or escaping. If this string is derived from user-controlled input, it may contain contain CRLF sequences, which an attacker can use to inject arbitrary IMAP commands. This issue has been patched in versions 0.4.24, 0.5.14, and 0.6.4.
- CVSS 4.0
- 5.8 MEDIUMCVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 0.43% probability · 36th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-77, CWE-93
- Affected
- ruby-lang/net\
- Source
- security-advisories@github.com
References
- https://github.com/ruby/net-imap/releases/tag/v0.4.24Release Notes
- https://github.com/ruby/net-imap/releases/tag/v0.5.14Release Notes
- https://github.com/ruby/net-imap/releases/tag/v0.6.4Release Notes
- https://github.com/ruby/net-imap/security/advisories/GHSA-hm49-wcqc-g2xgMitigation, Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.