CVE-2026-47241
LowCVSS 2.1Exploitation Probability (EPSS)
Low risk15th percentile - higher than 15% of all known CVEs
Summary
Net::IMAP in Ruby prior to versions 0.6.5 and 0.5.15 has a vulnerability that allows an attacker to inject additional commands. By exploiting improperly validated arguments, an attacker can force the first command to wait for another command to finish.
Risk Assessment
The organization may be exposed to attacks that could lead to communication being blocked in the IMAP system, potentially affecting email service availability.
Recommendation
It is recommended to upgrade to versions 0.6.5 or 0.5.15 to eliminate this vulnerability and secure the system against potential attacks.
Other vulnerabilities in Net::IMAP
See all- CVE-2026-42257Critical
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 CRLF sequences, which an attacker can use to inject arbitrary IMAP commands.
- CVE-2026-47242Medium
The Net::IMAP library in Ruby has a vulnerability that allows arbitrary IMAP command injection due to improper validation of arguments in the #id and #enable methods. This issue affects versions prior to 0.6.5 and 0.5.15.
- CVE-2026-47240Medium
The Net::IMAP library in Ruby has a vulnerability that allows arbitrary IMAP command injection if the server does not support non-synchronizing literals. Versions prior to 0.6.5 and 0.5.15 are susceptible to an attack that may lead to unauthorized command execution.
- CVE-2026-42258Medium
The Net::IMAP library in Ruby before versions 0.4.24, 0.5.14, and 0.6.4 is vulnerable to CRLF injection / IMAP command injection via symbol arguments passed to IMAP commands.
- CVE-2026-42256Medium
In Net::IMAP for Ruby (versions 0.4.0 to before 0.4.24, 0.5.0 to before 0.5.14, 0.6.0 to before 0.6.4), when authenticating with SCRAM-SHA1 or SCRAM-SHA256, a hostile server can perform a computational denial-of-service attack by sending a large iteration count value.
- CVE-2026-42246High
In the Net::IMAP library for Ruby prior to versions 0.3.10, 0.4.24, 0.5.14, and 0.6.4, a man-in-the-middle attacker can cause the starttls method to return 'successfully' without actually starting TLS.
- CVE-2026-42245High
Net::IMAP in Ruby has quadratic time complexity when reading large responses containing many string literals. A hostile server can send crafted responses to exhaust the client's CPU, leading to a denial of service (DoS) attack.
Original NVD description (English source)
Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. Prior to 0.6.5 and 0.5.15, several Net::IMAP commands accept a raw string argument which is only validated to prevent CRLF injection and then sent verbatim. If this string is derived from user-controlled input, an attacker can force the next command to be absorbed as a continuation of the first command. This will cause the first command to eventually fail, but also prevents it from returning until another command is sent (from another thread). That other command will not return until the connection is closed. This vulnerability is fixed in 0.6.5 and 0.5.15.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS