CVE-2026-42245
HIGH7.5EPSS 0.09%net-imap has quadratic complexity when reading response literals
Published: 5/4/2026Modified: 5/19/2026
Description
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, Net::IMAP::ResponseReader has quadratic time complexity when reading large responses containing many string literals. A hostile server can send responses which are crafted to exhaust the client's CPU for a denial of service attack. This issue has been patched in versions 0.4.24, 0.5.14, and 0.6.4.
Affected packages (4)
- Debian/ruby2.7from 0
- Debian/ruby3.1from 0
- Debian/ruby3.3from 0
- RubyGems/net-imap>= 0.6.0, < 0.6.4
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 4.0 | — | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N |
| osv | CVSS 3.1 | HIGH7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
References (11)
- ADVISORYhttps://nvd.nist.gov/vuln/detail/CVE-2026-42245
- ADVISORYhttps://security-tracker.debian.org/tracker/CVE-2026-42245
- PATCHhttps://github.com/ruby/net-imap
- WEBhttps://github.com/ruby/net-imap/commit/6091f7d6b1f3514cafbfe39c76f2b5d73de3ca96
- WEBhttps://github.com/ruby/net-imap/commit/88d95231fc8afef11c1f074453f7d75b68c9dfda
- WEBhttps://github.com/ruby/net-imap/commit/de685f91a4a4cc75eb80da898c2bf8af08d34819
- WEBhttps://github.com/ruby/net-imap/releases/tag/v0.4.24
- WEBhttps://github.com/ruby/net-imap/releases/tag/v0.5.14
- WEBhttps://github.com/ruby/net-imap/releases/tag/v0.6.4
- WEBhttps://github.com/ruby/net-imap/security/advisories/GHSA-q2mw-fvj9-vvcw
- WEBhttps://github.com/rubysec/ruby-advisory-db/blob/master/gems/net-imap/CVE-2026-42245.yml