ruby net-imap up to 0.5.14 Net::IMAP command injection

Summaryinfo

A vulnerability marked as critical has been reported in ruby net-imap up to 0.5.14. This affects the function Net::IMAP. The manipulation leads to command injection. This vulnerability is listed as CVE-2026-47242. The attack must be carried out locally. There is no available exploit. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in ruby net-imap up to 0.5.14 and classified as critical. This issue affects the function Net::IMAP. The manipulation with an unknown input leads to a command injection vulnerability. Using CWE to declare the problem leads to CWE-77. The product constructs all or part of a command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended command when it is sent to a downstream component. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

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.

It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2026-47242 since 05/19/2026. The exploitation is known to be easy. Attacking locally is a requirement. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1202 according to MITRE ATT&CK.

Upgrading to version 0.5.15 or 0.6.4.1 eliminates this vulnerability.

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Productinfo

Type

• Programming Language Software

Vendor

• ruby

Name

• net-imap

Version

• 0.5.0
• 0.5.1
• 0.5.2
• 0.5.3
• 0.5.4
• 0.5.5
• 0.5.6
• 0.5.7
• 0.5.8
• 0.5.9
• 0.5.10
• 0.5.11
• 0.5.12
• 0.5.13
• 0.5.14

License

• open-source

Website

• Product: https://github.com/ruby/net-imap/

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