CVE-2026-42256 (GCVE-0-2026-42256)
Vulnerability from cvelistv5
Published
2026-05-09 19:38
Modified
2026-05-11 17:04
CWE
  • CWE-1322 - Use of Blocking Code in Single-threaded, Non-blocking Context
  • CWE-770 - Allocation of Resources Without Limits or Throttling
Summary
Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. From versions 0.4.0 to before 0.4.24, 0.5.0 to before 0.5.14, and 0.6.0 to before 0.6.4, when authenticating a connection with SCRAM-SHA1 or SCRAM-SHA256, a hostile server can perform a computational denial-of-service attack on the client process by sending a big iteration count value. This issue has been patched in versions 0.4.24, 0.5.14, and 0.6.4.
Impacted products
Vendor Product Version
ruby net-imap Version: >= 0.4.0, < 0.4.24
Version: >= 0.5.0, < 0.5.14
Version: >= 0.6.0, < 0.6.4
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Show details on NVD website


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  • Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
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