CVE-2026-42258
MEDIUMDescription
Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. Prior to versions 0.4.24, 0.5.14, and 0.6.4, symbol arguments to commands are vulnerable to a CRLF Injection / IMAP Command injection via Symbol arguments passed to IMAP commands. This issue has been patched in versions 0.4.24, 0.5.14, and 0.6.4.
How to fix
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.
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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
Impact
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:L
Exploit Intelligence
Moderate risk: more likely to be exploited than 54% of all known CVEs.
References
- access.redhat.com
- access.redhat.com
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- access.redhat.com
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- access.redhat.com
- access.redhat.com
- access.redhat.com
- access.redhat.com
- access.redhat.com
- access.redhat.com
- access.redhat.com
- access.redhat.com
- access.redhat.com
- access.redhat.com
- access.redhat.com
- bugzilla.redhat.com
- security.access.redhat.com
Related Vulnerabilities
Other CWE-77 (Command Injection) vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2024-3400 | Critical | 10.0 | 100% | KEV + Ransom | - |
| CVE-2024-21887 | Critical | 9.1 | 100% | KEV + Ransom | - |
| CVE-2023-1671 | Critical | 9.8 | 100% | KEV | Fix |
| CVE-2023-1389 | High | 8.8 | 100% | KEV | Fix |
| CVE-2021-1498 | Critical | 9.8 | 100% | KEV | Fix |
| CVE-2012-1823 | Critical | 9.8 | 100% | KEV | Fix |
Common questions
How do I fix CVE-2026-42258?
Published advisories record a fix for 178 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-2026-42258 being actively exploited?
Not that we know of. CVE-2026-42258 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.78% is the estimated probability that it will be exploited in the next 30 days. That is higher than 54% of all scored CVEs.
How severe is CVE-2026-42258?
CVE-2026-42258 has a CVSS v3 base score of 5.3, rated moderate. 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-2026-42258 affect?
Published advisories record a fix for ruby3.4 (Amazon), ruby3.4-bundled-gems (Amazon), ruby3.4-bundled-gems-debuginfo (Amazon), ruby3.4-debuginfo (Amazon), and 174 more. The list on this page is capped, so there may be more.
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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.