CVE-2025-43857 Information

Description

Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. Prior to versions 0.5.7 0.4.20 0.3.9 and 0.2.5 there is a possibility for denial of service by memory exhaustion when net-imap reads server responses. At any time while the client is connected a malicious server can send can send a \literal\ byte count which is automatically read by the client’s receiver thread. The response reader immediately allocates memory for the number of bytes indicated by the server response. This should not be an issue when securely connecting to trusted IMAP servers that are well-behaved. It can affect insecure connections and buggy untrusted or compromised servers (for example connecting to a user supplied hostname). This issue has been patched in versions 0.5.7 0.4.20 0.3.9 and 0.2.5.

Reference

https://github.com/ruby/net-imap/pull/442 https://github.com/ruby/net-imap/pull/444/commits/0ae8576c1a90bcd9573f81bdad4b4b824642d105#diff-53721cb4d9c3fb86b95cc8476ca2df90968ad8c481645220c607034399151462 https://github.com/ruby/net-imap/pull/445 https://github.com/ruby/net-imap/pull/446 https://github.com/ruby/net-imap/pull/447 https://github.com/ruby/net-imap/security/advisories/GHSA-j3g3-5qv5-52mj