CVE-2026-42246
net-imap vulnerable to STARTTLS stripping via invalid response timing
CVSS Score
7.4
EPSS Score
0.0%
EPSS Percentile
0th
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 | CWE-392 CWE-393 CWE-754 CWE-636 CWE-841 |
| Vendor | ruby |
| Product | net-imap |
| Ecosystems | |
| Industries | Technology |
| Published | May 9, 2026 |
| Last Updated | Jul 15, 2026 |
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Affected Versions
ruby / net-imap
< 0.3.10 >= 0.4.0, < 0.4.24 >= 0.5.0, < 0.5.14 >= 0.6.0, < 0.6.4
References
github.com: https://github.com/ruby/net-imap/security/advisories/GHSA-vcgp-9326-pqcp github.com: https://github.com/ruby/net-imap/commit/0ede4c40b1523dfeaf95777b2678e54cc0fd9618 github.com: https://github.com/ruby/net-imap/commit/24a4e770b43230286a05aa2a9746cdbb3eb8485e github.com: https://github.com/ruby/net-imap/commit/97e2488fb5401a1783bddd959dde007d9fbce42c github.com: https://github.com/ruby/net-imap/commit/f79d35bf5833f186e81044c57c843eda30c873da github.com: https://github.com/ruby/net-imap/releases/tag/v0.3.10 github.com: https://github.com/ruby/net-imap/releases/tag/v0.4.24 github.com: https://github.com/ruby/net-imap/releases/tag/v0.5.14 access.redhat.com: https://access.redhat.com/security/cve/CVE-2026-42246 bugzilla.redhat.com: https://bugzilla.redhat.com/show_bug.cgi?id=2468499 security.access.redhat.com: https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42246.json access.redhat.com: https://access.redhat.com/errata/RHSA-2026:37397 access.redhat.com: https://access.redhat.com/errata/RHSA-2026:35895 access.redhat.com: https://access.redhat.com/errata/RHSA-2026:33565 access.redhat.com: https://access.redhat.com/errata/RHSA-2026:33540 access.redhat.com: https://access.redhat.com/errata/RHSA-2026:33514 access.redhat.com: https://access.redhat.com/errata/RHSA-2026:33515 access.redhat.com: https://access.redhat.com/errata/RHSA-2026:35866 access.redhat.com: https://access.redhat.com/errata/RHSA-2026:35867 access.redhat.com: https://access.redhat.com/errata/RHSA-2026:34076 access.redhat.com: https://access.redhat.com/errata/RHSA-2026:35834 access.redhat.com: https://access.redhat.com/errata/RHSA-2026:33630 access.redhat.com: https://access.redhat.com/errata/RHSA-2026:36099 access.redhat.com: https://access.redhat.com/errata/RHSA-2026:33462 access.redhat.com: https://access.redhat.com/errata/RHSA-2026:37238 access.redhat.com: https://access.redhat.com/errata/RHSA-2026:33512 access.redhat.com: https://access.redhat.com/errata/RHSA-2026:33576 access.redhat.com: https://access.redhat.com/errata/RHSA-2026:33577 access.redhat.com: https://access.redhat.com/errata/RHSA-2026:33721 access.redhat.com: https://access.redhat.com/errata/RHSA-2026:33552 access.redhat.com: https://access.redhat.com/errata/RHSA-2026:33551