CVE & CISA-KEV Catalog

CVE-2026-42246

HIGH
7.4
CVSS v3
NVD

Description

Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. Prior to versions 0.3.10, 0.4.24, 0.5.14, and 0.6.4, a man-in-the-middle attacker can cause Net::IMAP#starttls to return "successfully", without starting TLS. This issue has been patched in versions 0.3.10, 0.4.24, 0.5.14, and 0.6.4.

How to fix

Remediation Available
rubyRed Hat / RHEL
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
rubyRocky
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
ruby-bundled-gemsRocky
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
ruby-bundled-gemsRed Hat / RHEL
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
ruby-bundled-gems-debuginfoRocky
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
ruby-bundled-gems-debuginfoRed Hat / RHEL
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
ruby-debuginfoRed Hat / RHEL
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
ruby-debuginfoRocky
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
ruby-debugsourceRed Hat / RHEL
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
ruby-debugsourceRocky
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
ruby-default-gemsRocky
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:4.0.3-33.module+el9.8.0+24428+77f1d00a.noarch::ruby:4.0RHSA-2026:33577
Fixed in:0:3.3.10-7.module+el9.8.0+24406+8975e57f.noarch::ruby:3.3RHSA-2026:33576
Fixed in:0:3.3.10-6.module+el9.6.0+24475+76cce029.noarch::ruby:3.3RHSA-2026:37238
Fixed in:0:3.3.10-7.module+el8.10.0+24407+4a33a056.noarch::ruby:3.3RHSA-2026:33515
Fixed in:0:3.3.10-7.module+el9.4.0+24474+8fc4d0bd.noarch::ruby:3.3RHSA-2026:36099
Fixed in:0:3.0.4-161.el9_2.3RHSA-2026:35834
ruby-default-gemsRed Hat / RHEL
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-7.module+el9.4.0+24474+8fc4d0bd.noarch::ruby:3.3RHSA-2026:36099
Fixed in:0:3.3.10-6.module+el9.6.0+24475+76cce029.noarch::ruby:3.3RHSA-2026:37238
Fixed in:0:4.0.3-33.module+el9.8.0+24428+77f1d00a.noarch::ruby:4.0RHSA-2026:33577
Fixed in:0:3.3.10-7.module+el8.10.0+24407+4a33a056.noarch::ruby:3.3RHSA-2026:33515
Fixed in:0:3.3.10-7.module+el9.8.0+24406+8975e57f.noarch::ruby:3.3RHSA-2026:33576
Fixed in:0:3.0.4-161.el9_2.3RHSA-2026:35834
ruby-develRocky
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
ruby-develRed Hat / RHEL
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
ruby-docRocky
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:2.0.0.648-39.el7_9.1RHSA-2026:37397
Fixed in:0:3.3.10-7.module+el8.10.0+24407+4a33a056.noarch::ruby:3.3RHSA-2026:33515
Fixed in:0:4.0.3-33.module+el9.8.0+24428+77f1d00a.noarch::ruby:4.0RHSA-2026:33577
Fixed in:0:2.5.9-109.module+el8.4.0+24479+aaeed2c5.noarch::ruby:2.5RHSA-2026:35866
Fixed in:0:2.5.9-112.module+el8.8.0+24452+e70e99ef.noarch::ruby:2.5RHSA-2026:34076
Fixed in:0:3.3.10-6.module+el9.6.0+24475+76cce029.noarch::ruby:3.3RHSA-2026:37238
ruby-docRed Hat / RHEL
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:2.0.0.648-39.el7_9.1RHSA-2026:37397
Fixed in:0:2.5.9-109.module+el8.4.0+24479+aaeed2c5.noarch::ruby:2.5RHSA-2026:35866
Fixed in:0:3.3.10-7.module+el8.10.0+24407+4a33a056.noarch::ruby:3.3RHSA-2026:33515
Fixed in:0:2.5.9-112.module+el8.6.0+24478+6e23d6ba.noarch::ruby:2.5RHSA-2026:35867
Fixed in:0:2.5.9-112.module+el8.8.0+24452+e70e99ef.noarch::ruby:2.5RHSA-2026:34076
Fixed in:0:3.3.10-6.module+el9.6.0+24475+76cce029.noarch::ruby:3.3RHSA-2026:37238
ruby-irbRocky
Fixed in:0:2.0.0.648-39.el7_9.1RHSA-2026:37397
Fixed in:0:2.5.9-112.module+el8.8.0+24452+e70e99ef.noarch::ruby:2.5RHSA-2026:34076
Fixed in:0:2.5.9-112.module+el8.6.0+24478+6e23d6ba.noarch::ruby:2.5RHSA-2026:35867
Fixed in:0:2.5.9-115.module+el8.10.0+24408+7ffaaa88.noarch::ruby:2.5RHSA-2026:33514
Fixed in:0:2.5.9-109.module+el8.4.0+24479+aaeed2c5.noarch::ruby:2.5RHSA-2026:35866
ruby-irbRed Hat / RHEL
Fixed in:0:2.0.0.648-39.el7_9.1RHSA-2026:37397
Fixed in:0:2.5.9-109.module+el8.4.0+24479+aaeed2c5.noarch::ruby:2.5RHSA-2026:35866
Fixed in:0:2.5.9-112.module+el8.6.0+24478+6e23d6ba.noarch::ruby:2.5RHSA-2026:35867
Fixed in:0:2.5.9-112.module+el8.8.0+24452+e70e99ef.noarch::ruby:2.5RHSA-2026:34076
Fixed in:0:2.5.9-115.module+el8.10.0+24408+7ffaaa88.noarch::ruby:2.5RHSA-2026:33514
ruby-libsRed Hat / RHEL
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
ruby-libsRocky
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
ruby-libs-debuginfoRed Hat / RHEL
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
ruby-libs-debuginfoRocky
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895
Fixed in:0:3.3.10-13.el10_2RHSA-2026:33565
ruby-tcltkRed Hat / RHEL
Fixed in:0:2.0.0.648-39.el7_9.1RHSA-2026:37397
Fixed in:0:2.0.0.648-39.el7_9.1RHSA-2026:37397
Fixed in:0:2.0.0.648-39.el7_9.1.ppc64RHSA-2026:37397
Fixed in:0:2.0.0.648-39.el7_9.1RHSA-2026:37397
ruby-tcltkRocky
Fixed in:0:2.0.0.648-39.el7_9.1RHSA-2026:37397
Fixed in:0:2.0.0.648-39.el7_9.1.ppc64RHSA-2026:37397
Fixed in:0:2.0.0.648-39.el7_9.1RHSA-2026:37397
Fixed in:0:2.0.0.648-39.el7_9.1RHSA-2026:37397
ruby3Red Hat / RHEL
Fixed in:4-main@aarch64RHSA-2026:38694
Fixed in:4-main@srcRHSA-2026:33552
Fixed in:4-main@srcRHSA-2026:38694
Fixed in:4-main@x86_64RHSA-2026:38694
Fixed in:3-main@srcRHSA-2026:33721
Fixed in:4-main@aarch64RHSA-2026:33552
Fixed in:3-main@x86_64RHSA-2026:33721
Fixed in:3-main@noarchRHSA-2026:33721
ruby3Rocky
Fixed in:3-main@x86_64RHSA-2026:33721
Fixed in:4-main@noarchRHSA-2026:33552
Fixed in:4-main@x86_64RHSA-2026:38694
Fixed in:4-main@aarch64RHSA-2026:38694
Fixed in:4-main@srcRHSA-2026:38694
Fixed in:4-main@x86_64RHSA-2026:33552
Fixed in:3-main@noarchRHSA-2026:33721
Fixed in:3-main@srcRHSA-2026:33721
ruby4Rocky
Fixed in:0-main@noarchRHSA-2026:33551
Fixed in:0-main@aarch64RHSA-2026:33551
Fixed in:0-main@srcRHSA-2026:33551
Fixed in:0-main@x86_64RHSA-2026:33551
ruby4Red Hat / RHEL
Fixed in:0-main@x86_64RHSA-2026:33551
Fixed in:0-main@srcRHSA-2026:33551
Fixed in:0-main@aarch64RHSA-2026:33551
Fixed in:0-main@noarchRHSA-2026:33551
ruby4.0Rocky
Fixed in:0:4.0.3-35.el10_2RHSA-2026:33540
Fixed in:0:4.0.3-35.el10_2RHSA-2026:33540
Fixed in:0:4.0.3-35.el10_2RHSA-2026:33540
Fixed in:0:4.0.3-35.el10_2RHSA-2026:33540
Fixed in:0:4.0.3-35.el10_2RHSA-2026:33540
ruby4.0Red Hat / RHEL
Fixed in:0:4.0.3-35.el10_2RHSA-2026:33540
Fixed in:0:4.0.3-35.el10_2RHSA-2026:33540
Fixed in:0:4.0.3-35.el10_2RHSA-2026:33540
Fixed in:0:4.0.3-35.el10_2RHSA-2026:33540
Fixed in:0:4.0.3-35.el10_2RHSA-2026:33540

This vulnerability affects an unusually large number of packages. The highest-confidence fixes are shown above; the full list is longer. Check the referenced advisories for complete coverage.

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

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 ComplexityHigh
Privileges RequiredNone
User InteractionNone
ScopeUnchanged

Impact

ConfidentialityHigh
IntegrityHigh
AvailabilityNone

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

Exploit Intelligence

0.31%probability of exploitation in 30 days
24thpercentile

Low risk: more likely to be exploited than 24% of all known CVEs.

References

Related Vulnerabilities

Other CWE-392 vulnerabilities, ordered by exploit likelihood. View all

CVESeverityCVSSEPSSExploitedFix
CVE-2024-12797Medium6.32.5%-Fix
CVE-2024-39697High8.60.7%--
CVE-2023-42444High8.60.7%-Fix
CVE-2023-48430Low2.70.6%-Fix
CVE-2017-2342High8.10.6%--
CVE-2023-42447High8.60.5%--

Common questions

How do I fix CVE-2026-42246?

Published advisories record a fix for 116 affected products. The "How to fix" section on this page lists the fixed version and source advisory for each one, so apply the entry matching what you actually run.

Is CVE-2026-42246 being actively exploited?

Not that we know of. CVE-2026-42246 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.31% is the estimated probability that it will be exploited in the next 30 days. That is higher than 24% of all scored CVEs.

How severe is CVE-2026-42246?

CVE-2026-42246 has a CVSS v3 base score of 7.4, rated important. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

What does CVE-2026-42246 affect?

Published advisories record a fix for ruby (Red Hat / RHEL), ruby (Rocky), ruby-bundled-gems (Rocky), ruby-bundled-gems (Red Hat / RHEL), and 112 more. The list on this page is capped, so there may be more.

Embed a live status badge for CVE-2026-42246
CVE-2026-42246 severity badge

Markdown

[![CVE-2026-42246](https://tridentstack.com/cve/badge/CVE-2026-42246.svg)](https://tridentstack.com/cve/CVE-2026-42246)

HTML

<a href="https://tridentstack.com/cve/CVE-2026-42246"><img src="https://tridentstack.com/cve/badge/CVE-2026-42246.svg" alt="CVE-2026-42246"></a>

Find and fix vulnerabilities across your fleet

TridentStack Control continuously scans your Windows, macOS, and Linux fleet for known vulnerabilities, prioritizes them by severity and active exploitation, and patches them automatically.

See how it worksStart freeThis CVE lookup is free and always will be.

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 2026-08-24.