CVE-2026-42245

Description

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, 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. This issue has been patched in versions 0.4.24, 0.5.14, and 0.6.4.

EPSS — Exploit Prediction

0.0009

Probability of exploitation

0.25%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-407 CWE-407

References

Other References

https://github.com/ruby/net-imap/commit/6091f7d6b1f3514cafbfe39c76f2b5d73de3ca96 https://github.com/ruby/net-imap/commit/88d95231fc8afef11c1f074453f7d75b68c9dfda https://github.com/ruby/net-imap/commit/de685f91a4a4cc75eb80da898c2bf8af08d34819 https://github.com/ruby/net-imap/releases/tag/v0.4.24 https://github.com/ruby/net-imap/releases/tag/v0.5.14 https://github.com/ruby/net-imap/releases/tag/v0.6.4 https://github.com/ruby/net-imap/security/advisories/GHSA-q2mw-fvj9-vvcw

Frequently Asked Questions

What is CVE-2026-42245? +

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, 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. This issue has been patched in versions 0.4.24, 0.5.14, and 0.6.4.

How do I check if I'm vulnerable to CVE-2026-42245? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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