CVE & CISA-KEV Catalog

CVE-2026-42256

MEDIUM
6.5
CVSS v3
NVD

Description

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.

How to fix

Remediation Available
ruby3Red Hat / RHEL
Fixed in:4-main@noarchRHSA-2026:33552
Fixed in:4-main@aarch64RHSA-2026:33552
Fixed in:4-main@srcRHSA-2026:33552
Fixed in:4-main@x86_64RHSA-2026:33552
Fixed in:3-main@noarchRHSA-2026:33721
Fixed in:3-main@x86_64RHSA-2026:33721
Fixed in:3-main@aarch64RHSA-2026:33721
Fixed in:3-main@srcRHSA-2026:33721
ruby3Rocky
Fixed in:4-main@aarch64RHSA-2026:33552
Fixed in:3-main@noarchRHSA-2026:33721
Fixed in:4-main@noarchRHSA-2026:33552
Fixed in:4-main@x86_64RHSA-2026:33552
Fixed in:3-main@aarch64RHSA-2026:33721
Fixed in:3-main@srcRHSA-2026:33721
Fixed in:3-main@x86_64RHSA-2026:33721
Fixed in:4-main@srcRHSA-2026:33552
ruby4Rocky
Fixed in:0-main@srcRHSA-2026:33551
Fixed in:0-main@x86_64RHSA-2026:33551
Fixed in:0-main@noarchRHSA-2026:33551
Fixed in:0-main@aarch64RHSA-2026:33551
ruby4Red Hat / RHEL
Fixed in:0-main@srcRHSA-2026:33551
Fixed in:0-main@aarch64RHSA-2026:33551
Fixed in:0-main@noarchRHSA-2026:33551
Fixed in:0-main@x86_64RHSA-2026:33551

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionRequired
ScopeUnchanged

Impact

ConfidentialityNone
IntegrityNone
AvailabilityHigh

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

Exploit Intelligence

0.30%probability of exploitation in 30 days
22ndpercentile

Low risk: more likely to be exploited than 22% of all known CVEs.

References

Related Vulnerabilities

Other CWE-770 (Allocation of Resources Without Limits or Throttling) vulnerabilities, ordered by exploit likelihood. View all

CVESeverityCVSSEPSSExploitedFix
CVE-2023-50387High7.5100%-Fix
CVE-2019-11478Medium5.395%-Fix
CVE-2019-11479High7.592%-Fix
CVE-2024-27316High7.591%-Fix
CVE-2022-30522High7.590%-Fix
CVE-2019-9515High7.588%-Fix
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Markdown

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-05-18.