Vulnerability · Published May 9, 2026 · Assigned by GitHub_M
CVE-2026-42245net-imap: Quadratic complexity when reading response literals
Low 2.3
In plain English
A low-severity security flaw in net-imap from ruby. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 35% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 4.0)2.3Low
Exploit odds (30 days)0.4%top 64.5% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official 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 & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux:10 | ruby | 3.3.10-13.el10_2 | ALSA-2026:33565 |
| AlmaLinux:8 | ruby | 3.3.10-7.module_el8.10.0+4210+b037b1ec | ALSA-2026:33515 |
| AlmaLinux:9 | ruby | 4.0.3-33.module_el9.8.0+273+a67497ba | ALSA-2026:33577 |
| AlmaLinux:9 | ruby | 3.3.10-7.module_el9.8.0+272+38177c5f | ALSA-2026:33576 |
| AlmaLinux:10 | ruby-bundled-gems | 3.3.10-13.el10_2 | ALSA-2026:33565 |
| AlmaLinux:8 | ruby-bundled-gems | 3.3.10-7.module_el8.10.0+4210+b037b1ec | ALSA-2026:33515 |
| AlmaLinux:9 | ruby-bundled-gems | 3.3.10-7.module_el9.8.0+272+38177c5f | ALSA-2026:33576 |
| AlmaLinux:9 | ruby-bundled-gems | 4.0.3-33.module_el9.8.0+273+a67497ba | ALSA-2026:33577 |
| AlmaLinux:10 | ruby-default-gems | 3.3.10-13.el10_2 | ALSA-2026:33565 |
| AlmaLinux:8 | ruby-default-gems | 3.3.10-7.module_el8.10.0+4210+b037b1ec | ALSA-2026:33515 |
| AlmaLinux:9 | ruby-default-gems | 3.3.10-7.module_el9.8.0+272+38177c5f | ALSA-2026:33576 |
| AlmaLinux:9 | ruby-default-gems | 4.0.3-33.module_el9.8.0+273+a67497ba | ALSA-2026:33577 |
| AlmaLinux:10 | ruby-devel | 3.3.10-13.el10_2 | ALSA-2026:33565 |
| AlmaLinux:8 | ruby-devel | 3.3.10-7.module_el8.10.0+4210+b037b1ec | ALSA-2026:33515 |
| AlmaLinux:9 | ruby-devel | 4.0.3-33.module_el9.8.0+273+a67497ba | ALSA-2026:33577 |
| AlmaLinux:9 | ruby-devel | 3.3.10-7.module_el9.8.0+272+38177c5f | ALSA-2026:33576 |
| AlmaLinux:10 | ruby-doc | 3.3.10-13.el10_2 | ALSA-2026:33565 |
| AlmaLinux:8 | ruby-doc | 3.3.10-7.module_el8.10.0+4210+b037b1ec | ALSA-2026:33515 |
| AlmaLinux:9 | ruby-doc | 3.3.10-7.module_el9.8.0+272+38177c5f | ALSA-2026:33576 |
| AlmaLinux:9 | ruby-doc | 4.0.3-33.module_el9.8.0+273+a67497ba | ALSA-2026:33577 |
| AlmaLinux:10 | ruby-libs | 3.3.10-13.el10_2 | ALSA-2026:33565 |
| AlmaLinux:8 | ruby-libs | 3.3.10-7.module_el8.10.0+4210+b037b1ec | ALSA-2026:33515 |
| AlmaLinux:9 | ruby-libs | 3.3.10-7.module_el9.8.0+272+38177c5f | ALSA-2026:33576 |
| AlmaLinux:9 | ruby-libs | 4.0.3-33.module_el9.8.0+273+a67497ba | ALSA-2026:33577 |
| AlmaLinux:10 | ruby4.0 | 4.0.3-35.el10_2 | ALSA-2026:33540 |
| AlmaLinux:10 | ruby4.0-devel | 4.0.3-35.el10_2 | ALSA-2026:33540 |
| AlmaLinux:10 | ruby4.0-doc | 4.0.3-35.el10_2 | ALSA-2026:33540 |
| AlmaLinux:10 | ruby4.0-rubygem-mysql2 | 0.5.7-35.el10_2 | ALSA-2026:33540 |
| AlmaLinux:10 | ruby4.0-rubygem-pg | 1.6.3-35.el10_2 | ALSA-2026:33540 |
| AlmaLinux:8 | rubygem-abrt | 0.4.0-1.module_el8.10.0+3799+191214cc | ALSA-2026:33515 |
| AlmaLinux:8 | rubygem-abrt-doc | 0.4.0-1.module_el8.10.0+3799+191214cc | ALSA-2026:33515 |
| AlmaLinux:10 | rubygem-bigdecimal | 3.1.5-13.el10_2 | ALSA-2026:33565 |
| AlmaLinux:8 | rubygem-bigdecimal | 3.1.5-7.module_el8.10.0+4210+b037b1ec | ALSA-2026:33515 |
| AlmaLinux:9 | rubygem-bigdecimal | 3.1.5-7.module_el9.8.0+272+38177c5f | ALSA-2026:33576 |
| AlmaLinux:9 | rubygem-bigdecimal | 4.0.1-33.module_el9.8.0+273+a67497ba | ALSA-2026:33577 |
| AlmaLinux:10 | rubygem-bundler | 2.5.22-13.el10_2 | ALSA-2026:33565 |
| AlmaLinux:8 | rubygem-bundler | 2.5.22-7.module_el8.10.0+4210+b037b1ec | ALSA-2026:33515 |
| AlmaLinux:9 | rubygem-bundler | 2.5.22-7.module_el9.8.0+272+38177c5f | ALSA-2026:33576 |
| AlmaLinux:9 | rubygem-bundler | 4.0.6-33.module_el9.8.0+273+a67497ba | ALSA-2026:33577 |
| AlmaLinux:10 | rubygem-io-console | 0.7.1-13.el10_2 | ALSA-2026:33565 |
| AlmaLinux:8 | rubygem-io-console | 0.7.1-7.module_el8.10.0+4210+b037b1ec | ALSA-2026:33515 |
| AlmaLinux:9 | rubygem-io-console | 0.7.1-7.module_el9.8.0+272+38177c5f | ALSA-2026:33576 |
| AlmaLinux:9 | rubygem-io-console | 0.8.2-33.module_el9.8.0+273+a67497ba | ALSA-2026:33577 |
| AlmaLinux:10 | rubygem-irb | 1.13.1-13.el10_2 | ALSA-2026:33565 |
| AlmaLinux:8 | rubygem-irb | 1.13.1-7.module_el8.10.0+4210+b037b1ec | ALSA-2026:33515 |
| AlmaLinux:9 | rubygem-irb | 1.16.0-33.module_el9.8.0+273+a67497ba | ALSA-2026:33577 |
| AlmaLinux:9 | rubygem-irb | 1.13.1-7.module_el9.8.0+272+38177c5f | ALSA-2026:33576 |
| AlmaLinux:10 | rubygem-json | 2.7.2-13.el10_2 | ALSA-2026:33565 |
| AlmaLinux:8 | rubygem-json | 2.7.2-7.module_el8.10.0+4210+b037b1ec | ALSA-2026:33515 |
| AlmaLinux:9 | rubygem-json | 2.18.0-33.module_el9.8.0+273+a67497ba | ALSA-2026:33577 |
| AlmaLinux:9 | rubygem-json | 2.7.2-7.module_el9.8.0+272+38177c5f | ALSA-2026:33576 |
| AlmaLinux:10 | rubygem-minitest | 5.20.0-13.el10_2 | ALSA-2026:33565 |
| AlmaLinux:8 | rubygem-minitest | 5.20.0-7.module_el8.10.0+4210+b037b1ec | ALSA-2026:33515 |
| AlmaLinux:9 | rubygem-minitest | 6.0.0-33.module_el9.8.0+273+a67497ba | ALSA-2026:33577 |
| AlmaLinux:9 | rubygem-minitest | 5.20.0-7.module_el9.8.0+272+38177c5f | ALSA-2026:33576 |
| AlmaLinux:8 | rubygem-mysql2 | 0.5.5-1.module_el8.10.0+3799+191214cc | ALSA-2026:33515 |
| AlmaLinux:9 | rubygem-mysql2 | 0.5.5-3.module_el9.7.0+184+e2e36072 | ALSA-2026:33576 |
| AlmaLinux:9 | rubygem-mysql2 | 0.5.7-1.module_el9.8.0+232+50f6dd36 | ALSA-2026:33577 |
| AlmaLinux:8 | rubygem-mysql2-doc | 0.5.5-1.module_el8.10.0+3799+191214cc | ALSA-2026:33515 |
| AlmaLinux:9 | rubygem-mysql2-doc | 0.5.7-1.module_el9.8.0+232+50f6dd36 | ALSA-2026:33577 |
| AlmaLinux:9 | rubygem-mysql2-doc | 0.5.5-3.module_el9.7.0+184+e2e36072 | ALSA-2026:33576 |
| AlmaLinux:8 | rubygem-pg | 1.5.4-1.module_el8.10.0+3799+191214cc | ALSA-2026:33515 |
| AlmaLinux:9 | rubygem-pg | 1.5.4-2.module_el9.7.0+245+447713a2 | ALSA-2026:33576 |
| AlmaLinux:9 | rubygem-pg | 1.6.3-1.module_el9.8.0+232+50f6dd36 | ALSA-2026:33577 |
| AlmaLinux:8 | rubygem-pg-doc | 1.5.4-1.module_el8.10.0+3799+191214cc | ALSA-2026:33515 |
| AlmaLinux:9 | rubygem-pg-doc | 1.6.3-1.module_el9.8.0+232+50f6dd36 | ALSA-2026:33577 |
| AlmaLinux:9 | rubygem-pg-doc | 1.5.4-2.module_el9.7.0+245+447713a2 | ALSA-2026:33576 |
| AlmaLinux:10 | rubygem-power_assert | 2.0.3-13.el10_2 | ALSA-2026:33565 |
| AlmaLinux:8 | rubygem-power_assert | 2.0.3-7.module_el8.10.0+4210+b037b1ec | ALSA-2026:33515 |
| AlmaLinux:9 | rubygem-power_assert | 3.0.1-33.module_el9.8.0+273+a67497ba | ALSA-2026:33577 |
| AlmaLinux:9 | rubygem-power_assert | 2.0.3-7.module_el9.8.0+272+38177c5f | ALSA-2026:33576 |
| AlmaLinux:10 | rubygem-psych | 5.1.2-13.el10_2 | ALSA-2026:33565 |
| AlmaLinux:8 | rubygem-psych | 5.1.2-7.module_el8.10.0+4210+b037b1ec | ALSA-2026:33515 |
| AlmaLinux:9 | rubygem-psych | 5.1.2-7.module_el9.8.0+272+38177c5f | ALSA-2026:33576 |
| AlmaLinux:9 | rubygem-psych | 5.3.1-33.module_el9.8.0+273+a67497ba | ALSA-2026:33577 |
| AlmaLinux:10 | rubygem-racc | 1.7.3-13.el10_2 | ALSA-2026:33565 |
| AlmaLinux:8 | rubygem-racc | 1.7.3-7.module_el8.10.0+4210+b037b1ec | ALSA-2026:33515 |
| AlmaLinux:9 | rubygem-racc | 1.7.3-7.module_el9.8.0+272+38177c5f | ALSA-2026:33576 |
| AlmaLinux:9 | rubygem-racc | 1.8.1-33.module_el9.8.0+273+a67497ba | ALSA-2026:33577 |
| AlmaLinux:10 | rubygem-rake | 13.1.0-13.el10_2 | ALSA-2026:33565 |
| AlmaLinux:8 | rubygem-rake | 13.1.0-7.module_el8.10.0+4210+b037b1ec | ALSA-2026:33515 |
| AlmaLinux:9 | rubygem-rake | 13.1.0-7.module_el9.8.0+272+38177c5f | ALSA-2026:33576 |
| AlmaLinux:9 | rubygem-rake | 13.3.1-33.module_el9.8.0+273+a67497ba | ALSA-2026:33577 |
| AlmaLinux:10 | rubygem-rbs | 3.4.0-13.el10_2 | ALSA-2026:33565 |
| AlmaLinux:8 | rubygem-rbs | 3.4.0-7.module_el8.10.0+4210+b037b1ec | ALSA-2026:33515 |
| AlmaLinux:9 | rubygem-rbs | 3.4.0-7.module_el9.8.0+272+38177c5f | ALSA-2026:33576 |
| AlmaLinux:9 | rubygem-rbs | 3.10.0-33.module_el9.8.0+273+a67497ba | ALSA-2026:33577 |
| AlmaLinux:10 | rubygem-rdoc | 6.6.3.1-13.el10_2 | ALSA-2026:33565 |
| AlmaLinux:8 | rubygem-rdoc | 6.6.3.1-7.module_el8.10.0+4210+b037b1ec | ALSA-2026:33515 |
| AlmaLinux:9 | rubygem-rdoc | 7.0.3-33.module_el9.8.0+273+a67497ba | ALSA-2026:33577 |
| AlmaLinux:9 | rubygem-rdoc | 6.6.3.1-7.module_el9.8.0+272+38177c5f | ALSA-2026:33576 |
| AlmaLinux:10 | rubygem-rexml | 3.4.4-13.el10_2 | ALSA-2026:33565 |
| AlmaLinux:8 | rubygem-rexml | 3.4.4-7.module_el8.10.0+4210+b037b1ec | ALSA-2026:33515 |
| AlmaLinux:9 | rubygem-rexml | 3.4.4-7.module_el9.8.0+272+38177c5f | ALSA-2026:33576 |
| AlmaLinux:9 | rubygem-rexml | 3.4.4-33.module_el9.8.0+273+a67497ba | ALSA-2026:33577 |
| AlmaLinux:10 | rubygem-rss | 0.3.1-13.el10_2 | ALSA-2026:33565 |
| AlmaLinux:8 | rubygem-rss | 0.3.1-7.module_el8.10.0+4210+b037b1ec | ALSA-2026:33515 |
| AlmaLinux:9 | rubygem-rss | 0.3.2-33.module_el9.8.0+273+a67497ba | ALSA-2026:33577 |
| AlmaLinux:9 | rubygem-rss | 0.3.1-7.module_el9.8.0+272+38177c5f | ALSA-2026:33576 |
| AlmaLinux:10 | rubygem-test-unit | 3.6.1-13.el10_2 | ALSA-2026:33565 |
| AlmaLinux:8 | rubygem-test-unit | 3.6.1-7.module_el8.10.0+4210+b037b1ec | ALSA-2026:33515 |
| AlmaLinux:9 | rubygem-test-unit | 3.7.5-33.module_el9.8.0+273+a67497ba | ALSA-2026:33577 |
| AlmaLinux:9 | rubygem-test-unit | 3.6.1-7.module_el9.8.0+272+38177c5f | ALSA-2026:33576 |
| AlmaLinux:10 | rubygem-typeprof | 0.21.9-13.el10_2 | ALSA-2026:33565 |
| AlmaLinux:8 | rubygem-typeprof | 0.21.9-7.module_el8.10.0+4210+b037b1ec | ALSA-2026:33515 |
| AlmaLinux:9 | rubygem-typeprof | 0.31.1-33.module_el9.8.0+273+a67497ba | ALSA-2026:33577 |
| AlmaLinux:9 | rubygem-typeprof | 0.21.9-7.module_el9.8.0+272+38177c5f | ALSA-2026:33576 |
| AlmaLinux:10 | rubygems | 3.5.22-13.el10_2 | ALSA-2026:33565 |
| AlmaLinux:8 | rubygems | 3.5.22-7.module_el8.10.0+4210+b037b1ec | ALSA-2026:33515 |
| AlmaLinux:9 | rubygems | 3.5.22-7.module_el9.8.0+272+38177c5f | ALSA-2026:33576 |
| AlmaLinux:9 | rubygems | 4.0.6-33.module_el9.8.0+273+a67497ba | ALSA-2026:33577 |
| AlmaLinux:10 | rubygems-devel | 3.5.22-13.el10_2 | ALSA-2026:33565 |
| AlmaLinux:8 | rubygems-devel | 3.5.22-7.module_el8.10.0+4210+b037b1ec | ALSA-2026:33515 |
| AlmaLinux:9 | rubygems-devel | 3.5.22-7.module_el9.8.0+272+38177c5f | ALSA-2026:33576 |
| AlmaLinux:9 | rubygems-devel | 4.0.6-33.module_el9.8.0+273+a67497ba | ALSA-2026:33577 |
| Alpine:v3.21 | ruby-net-imap | 0.4.25-r0 | ALPINE-CVE-2026-42245 |
| Debian:12 | ruby3.1 | no fix listed | DEBIAN-CVE-2026-42245 |
| Debian:13 | ruby3.3 | no fix listed | DEBIAN-CVE-2026-42245 |
| Debian:14 | ruby3.3 | no fix listed | DEBIAN-CVE-2026-42245 |
| Rocky Linux:10 | ruby | 0:3.3.10-13.el10_2 | RLSA-2026:33565 |
| Rocky Linux:10 | ruby4.0 | 0:4.0.3-35.el10_2 | RLSA-2026:33540 |
| Rocky Linux:8 | rubygem-abrt | 0:0.4.0-1.module+el8.10.0+1826+b62220b4 | RLSA-2026:33515 |
| Rocky Linux:8 | rubygem-abrt | 0:0.4.0-1.module+el8.10.0+1679+61871737 | RLSA-2026:33515 |
| Rocky Linux:8 | rubygem-abrt | 0:0.4.0-1.module+el8.10.0+1741+bdb5b6ca | RLSA-2026:33515 |
| Rocky Linux:8 | rubygem-abrt | 0:0.4.0-1.module+el8.10.0+1827+16ecb9d2 | RLSA-2026:33515 |
| Rocky Linux:8 | rubygem-abrt | 0:0.4.0-1.module+el8.5.0+668+665814fa | RLSA-2026:33515 |
| Rocky Linux:8 | rubygem-abrt | 0:0.4.0-1.module+el8.10.0+1820+f3fffb92 | RLSA-2026:33515 |
| Rocky Linux:8 | rubygem-abrt | 0:0.4.0-1.module+el8.9.0+1537+0b2034bd | RLSA-2026:33515 |
| Rocky Linux:8 | rubygem-mysql2 | 0:0.5.5-1.module+el8.10.0+1679+61871737 | RLSA-2026:33515 |
| Rocky Linux:8 | rubygem-mysql2 | 0:0.5.5-1.module+el8.10.0+1827+16ecb9d2 | RLSA-2026:33515 |
| Rocky Linux:9 | rubygem-mysql2 | 0:0.5.5-3.module+el9.7.0+40032+36e56d0d | RLSA-2026:33576 |
| Rocky Linux:9 | rubygem-mysql2 | 0:0.5.7-1.module+el9.8.0+40094+ce01217c | RLSA-2026:33577 |
| Rocky Linux:8 | rubygem-pg | 0:1.5.4-1.module+el8.10.0+1827+16ecb9d2 | RLSA-2026:33515 |
| Rocky Linux:8 | rubygem-pg | 0:1.5.4-1.module+el8.10.0+1679+61871737 | RLSA-2026:33515 |
| Rocky Linux:9 | rubygem-pg | 0:1.5.4-2.module+el9.7.0+40188+314ad260.0.1 | RLSA-2026:33576 |
| Rocky Linux:9 | rubygem-pg | 0:1.6.3-1.module+el9.8.0+40094+ce01217c | RLSA-2026:33577 |
| RubyGems | net-imap | 0.6.4 | GHSA-q2mw-fvj9-vvcw |
| RubyGems | net-imap | 0.5.14 | GHSA-q2mw-fvj9-vvcw |
| RubyGems | net-imap | 0.4.24 | GHSA-q2mw-fvj9-vvcw |
| Ubuntu:25.10 | jruby | no fix listed | UBUNTU-CVE-2026-42245 |
| Ubuntu:26.10 | jruby | no fix listed | UBUNTU-CVE-2026-42245 |
| Ubuntu:25.10 | ruby3.3 | no fix listed | UBUNTU-CVE-2026-42245 |
| Ubuntu:26.10 | ruby3.3 | no fix listed | UBUNTU-CVE-2026-42245 |
Affected products (as reported)
Weakness: CWE-407 · Vector: 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
References
- https://github.com/ruby/net-imap/security/advisories/GHSA-q2mw-fvj9-vvcw x_refsource_CONFIRM
- https://github.com/ruby/net-imap/commit/6091f7d6b1f3514cafbfe39c76f2b5d73de3ca96 x_refsource_MISC
- https://github.com/ruby/net-imap/commit/88d95231fc8afef11c1f074453f7d75b68c9dfda x_refsource_MISC
- https://github.com/ruby/net-imap/commit/de685f91a4a4cc75eb80da898c2bf8af08d34819 x_refsource_MISC
- https://github.com/ruby/net-imap/releases/tag/v0.4.24 x_refsource_MISC
- https://github.com/ruby/net-imap/releases/tag/v0.5.14 x_refsource_MISC
- https://github.com/ruby/net-imap/releases/tag/v0.6.4 x_refsource_MISC