CVE-2026-47242
CVE-2026-47242 is a medium-severity vulnerability with a CVSS 4.0 base score of 5.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-77.
Key facts
- Severity: Medium (CVSS 4.0 base score 5.8)
- EPSS exploit prediction: 0% (3rd percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2026-38353
- Weakness: CWE-77
- Published:
- Last modified:
Description
Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. Prior to 0.6.5 and 0.5.15, when Net::IMAP#id is called with a hash argument, although the ID field value strings are correctly quoted (escaping quoted specials), they were not validated to prohibit CRLF sequences. While Net::IMAP#enable does process its arguments for aliases, it does not validate them as valid atoms (or as a list of valid atoms). The #to_s value is sent verbatim. Arguments to either command could be used by an attacker to inject arbitrary IMAP commands. This vulnerability is fixed in 0.6.5 and 0.5.15.
Frequently asked questions
- What is CVE-2026-47242?
- Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. Prior to 0.6.5 and 0.5.15, when Net::IMAP#id is called with a hash argument, although the ID field value strings are correctly quoted (escaping quoted specials), they were not validated to prohibit CRLF sequences. While Net::IMAP#enable does process its arguments for aliases, it does not validate them as valid atoms (or as a list of valid atoms). The #to_s value is sent verbatim. Arguments to either command could be used by an attacker to inject arbitrary IMAP commands. This vulnerability is fixed in 0.6.5 and 0.5.15.
- How severe is CVE-2026-47242?
- CVE-2026-47242 has a CVSS 4.0 base score of 5.8, rated medium severity.
- Is CVE-2026-47242 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (3rd percentile), an estimate of the probability of exploitation in the next 30 days.
- How do I fix CVE-2026-47242?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
- Does CVE-2026-47242 have an EU (EUVD) identifier?
- Yes. CVE-2026-47242 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-38353.
- When was CVE-2026-47242 published?
- CVE-2026-47242 was published on 2026-06-22 and last updated on 2026-06-23.
References
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