Resource exhaustion in Ruby Net-imap

CVE-2026-42256

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-S…

EPSS: 0.000 (14.5th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-42256?
CVE-2026-42256 is a medium-severity vulnerability in Ruby Net-imap, classified under Allocation of Resources Without Limits or Throttling. CVSS score: 6.5/10. Published 2026-05-09.
How severe is CVE-2026-42256?
Medium severity. CVSS v3 base score is 6.5 out of 10.