CVE-2026-42246

HIGH

7.4

CVSS v3

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.

CWE-392 CWE-393 CWE-636 CWE-754 CWE-841 CWE-325

How to fix

Remediation Available

rubyRed 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:0:3.3.10-13.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

rubyRocky

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

ruby-bundled-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:0:3.3.10-11.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-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

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:0:3.3.10-13.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-bundled-gems-debuginfoRed 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:0:3.3.10-13.el10_2RHSA-2026:33565

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:0:3.3.10-13.el10_2RHSA-2026:33565

ruby-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:0:3.3.10-13.el10_2RHSA-2026:33565

ruby-debugsourceRed 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:0:3.3.10-13.el10_2RHSA-2026:33565

ruby-debugsourceRocky

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-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:0:3.3.10-7.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:0:3.3.10-7.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:0:3.0.7-165.el9_6.1RHSA-2026:33462

Fixed in:0:3.0.7-162.el9_4.3RHSA-2026:33630

ruby-default-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:0:3.3.10-7.module+el8.10.0+24407+4a33a056.noarch::ruby:3.3RHSA-2026:33515

Fixed in:0:3.0.7-167.el9_8RHSA-2026:33512

Fixed in:0:3.0.7-165.el9_6.1RHSA-2026:33462

Fixed in:0:3.0.4-161.el9_2.3RHSA-2026:35834

Fixed in:0:3.3.10-7.module+el9.8.0+24406+8975e57f.noarch::ruby:3.3RHSA-2026:33576

Fixed in:0:4.0.3-33.module+el9.8.0+24428+77f1d00a.noarch::ruby:4.0RHSA-2026:33577

ruby-develRed 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:0:3.3.10-13.el10_2RHSA-2026:33565

Fixed in:0:3.3.10-11.el10_0.2RHSA-2026:35895

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

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:0:2.5.9-109.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:0:3.3.10-7.module+el8.10.0+24407+4a33a056.noarch::ruby:3.3RHSA-2026:33515

Fixed in:0:2.5.9-115.module+el8.10.0+24408+7ffaaa88.noarch::ruby:2.5RHSA-2026:33514

Fixed in:0:2.5.9-112.module+el8.8.0+24452+e70e99ef.noarch::ruby:2.5RHSA-2026:34076

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:0:2.5.9-112.module+el8.6.0+24478+6e23d6ba.noarch::ruby:2.5RHSA-2026:35867

Fixed in:0:3.3.10-7.module+el8.10.0+24407+4a33a056.noarch::ruby:3.3RHSA-2026:33515

Fixed in:0:2.5.9-109.module+el8.4.0+24479+aaeed2c5.noarch::ruby:2.5RHSA-2026:35866

Fixed in:0:2.5.9-115.module+el8.10.0+24408+7ffaaa88.noarch::ruby:2.5RHSA-2026:33514

Fixed in:0:2.5.9-112.module+el8.8.0+24452+e70e99ef.noarch::ruby:2.5RHSA-2026:34076

ruby-irbRed Hat / RHEL

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:0:2.5.9-109.module+el8.4.0+24479+aaeed2c5.noarch::ruby:2.5RHSA-2026:35866

Fixed in:0:2.5.9-115.module+el8.10.0+24408+7ffaaa88.noarch::ruby:2.5RHSA-2026:33514

ruby-irbRocky

Fixed in:0:2.0.0.648-39.el7_9.1RHSA-2026:37397

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:0:2.5.9-112.module+el8.8.0+24452+e70e99ef.noarch::ruby:2.5RHSA-2026:34076

Fixed in:0:2.5.9-109.module+el8.4.0+24479+aaeed2c5.noarch::ruby:2.5RHSA-2026:35866

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

ruby-libsRocky

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-libs-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:0:3.3.10-13.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-libs-debuginfoRed 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

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

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_9.1.ppc64RHSA-2026:37397

Fixed in:0:2.0.0.648-39.el7_9.1RHSA-2026:37397

ruby4.0Red Hat / RHEL

Fixed in:0:4.0.3-35.el10_2RHSA-2026:33540

ruby4.0Rocky

Fixed in:0:4.0.3-35.el10_2RHSA-2026:33540

ruby4.0-debuginfoRocky

Fixed in:0:4.0.3-35.el10_2RHSA-2026:33540

ruby4.0-debuginfoRed Hat / RHEL

Fixed in:0:4.0.3-35.el10_2RHSA-2026:33540

ruby4.0-debugsourceRocky

Fixed in:0:4.0.3-35.el10_2RHSA-2026:33540

ruby4.0-debugsourceRed Hat / RHEL

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

22ndpercentile

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

References

Related Vulnerabilities

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

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2024-12797	Medium	6.3	2.5%	-	Fix
CVE-2023-42444	High	8.6	0.9%	-	Fix
CVE-2024-39697	High	8.6	0.7%	-	-
CVE-2023-42447	High	8.6	0.6%	-	-
CVE-2023-48430	Low	2.7	0.6%	-	Fix
CVE-2017-2342	High	8.1	0.6%	-	-

Common questions

How do I fix CVE-2026-42246?

Published advisories record a fix for 112 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 22% 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 108 more. The list on this page is capped, so there may be more.

Embed a live status badge for CVE-2026-42246

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 2026-08-24.