net-imap has quadratic complexity when reading response literals — CVE-2026-42245

Summary

### Summary `Net::IMAP::ResponseReader` has quadratic time complexity when reading large responses containing many string literals. A hostile server can send responses which are crafted to exhaust the client's CPU for a denial of service attack. ### Details For each literal in a response, `ResponseReader` rescans the entire growing response buffer. The regular expression that is used to scan the response buffer…

Product

rubygems: net-imap

What to do

General, cautious steps (verify details in the official source):

• Review exposure and plan remediation based on risk and environment.
• Identify affected product versions in your inventory and verify whether you are impacted.
• Apply vendor patches/updates or recommended mitigations as soon as available.
• Read the official advisory for exact affected versions and remediation steps.

Official advisory

• Read the official source
• CVE Record
• NVD

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