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Vulnerabilities

Vulnerability · CVE-2026-42256

Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby.

Published May 9, 2026 · catalog updated Jul 24, 2026 · Net::IMAP implements Internet Message

Check if you run it

No confirmed exploitation is on record for CVE-2026-42256. EPSS is 0.52%. Act only if a listed version of Net::IMAP implements Internet Message is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (Net::IMAP implements Internet Message).
  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Medium6.0
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.52%
Remediation
Advisory link
Affected products
cpe ruby-lang/net

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe ruby-lang/net\

How to fix CVE-2026-42256

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-42256. EPSS is 0.52%. Act only if a listed version of Net::IMAP implements Internet Message is installed.

Which versions are affected?

Compare what you have installed with \. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-1322; CWE-770: Allocation of Resources Without Limits or Throttling. EPSS 0.52%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. May 9, 2026 · NIST NVD

    Detected

    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 pa

  2. Jul 24, 2026 · NIST NVD

    Updated

    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 pa

Sources

  • CVE.orgVulnerability recordCVE-2026-42256

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-42256

    30-day exploitation probability 0.5%

    first.org
  • NIST NVDVulnerability recordCVE-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-SHA256, a hostile server can perform a com

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.