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TI-2026-30562 Aliases CVE-2026-42245GHSA-q2mw-fvj9-vvcw

net-imap: Quadratic complexity when reading response literals

Priority LOW 12CWE-407Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Passive
Attack complexity
Low
Attack requirements
Present
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · Low
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-407.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.0041 35th percentileScored 2026-11-07
Fix Fixed net-imap (ruby): 0.4.24, 0.5.14, 0.6.4net-imap (RubyGems): 0.6.4, 0.5.14, 0.4.24Red Hat: 12 advisories

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
rubynet-imapbefore 0.4.24; 0.5.0 to before 0.5.14; 0.6.0 to before 0.6.40.4.24, 0.5.14, 0.6.4Patch availableCNA
—net-imap (RubyGems)0.6.0 to before 0.6.40.6.4Patch availableGHSA-q2mw-fvj9-vvcw
—net-imap (RubyGems)0.5.0 to before 0.5.140.5.14Patch availableGHSA-q2mw-fvj9-vvcw
—net-imap (RubyGems)before 0.4.240.4.24Patch availableGHSA-q2mw-fvj9-vvcw
  • net-imap Vendorruby Affected before 0.4.24; 0.5.0 to before 0.5.14; 0.6.0 to before 0.6.4 Fixed in 0.4.24, 0.5.14, 0.6.4 Patch available CNA
  • net-imap (RubyGems) Vendor— Affected 0.6.0 to before 0.6.4 Fixed in 0.6.4 Patch available GHSA-q2mw-fvj9-vvcw
  • net-imap (RubyGems) Vendor— Affected 0.5.0 to before 0.5.14 Fixed in 0.5.14 Patch available GHSA-q2mw-fvj9-vvcw
  • net-imap (RubyGems) Vendor— Affected before 0.4.24 Fixed in 0.4.24 Patch available GHSA-q2mw-fvj9-vvcw

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:ruby-lang:net\:\:imap:*:*:*:*:*:ruby:*:* imapVulnerableruby
  • cpe:2.3:a:ruby-lang:net\:\:imap:*:*:*:*:*:ruby:*:* Versions imap Vulnerable ·ruby

Remediation

  • Fix · CNA net-imap (ruby) Fixed in 0.4.24, 0.5.14, 0.6.4
  • Fix · GHSA-q2mw-fvj9-vvcw net-imap (RubyGems) Fixed in 0.6.4 Advisory →
  • Fix · GHSA-q2mw-fvj9-vvcw net-imap (RubyGems) Fixed in 0.5.14 Advisory →
  • Fix · GHSA-q2mw-fvj9-vvcw net-imap (RubyGems) Fixed in 0.4.24 Advisory →

Red Hat 12 advisories

  • RHSA-2026:38694 Released 2026-07-13 · Red Hat rating Important
    Red Hat Hardened Images RPMs Security Update
    • Red Hat Hardened Images ruby3.4-3.4.10-31.hum1@aarch64, ruby3.4-3.4.10-31.hum1@src, ruby3.4-3.4.10-31.hum1@x86_64 +46
  • RHSA-2026:37238 Released 2026-07-09 · Red Hat rating Important
    ruby:3.3 security update
    • Red Hat Enterprise Linux AppStream EUS (v.9.6) ruby-3.3.10-6.module+el9.6.0+24475+76cce029.aarch64::ruby:3.3, ruby-3.3.10-6.module+el9.6.0+24475+76cce029.i686::ruby:3.3, ruby-3.3.10-6.module+el9.6.0+24475+76cce029.ppc64le::ruby:3.3 +47
  • RHSA-2026:36099 Released 2026-07-07 · Red Hat rating Important
    ruby:3.3 security update
    • Red Hat Enterprise Linux AppStream E4S (v.9.4) ruby-3.3.10-7.module+el9.4.0+24474+8fc4d0bd.aarch64::ruby:3.3, ruby-3.3.10-7.module+el9.4.0+24474+8fc4d0bd.i686::ruby:3.3, ruby-3.3.10-7.module+el9.4.0+24474+8fc4d0bd.ppc64le::ruby:3.3 +47
Show 9 more Red Hat advisories
  • RHSA-2026:35895 Released 2026-07-06 · Red Hat rating Important
    ruby security update
    • Red Hat Enterprise Linux AppStream EUS (v. 10.0) ruby-3.3.10-11.el10_0.2, ruby-bundled-gems-3.3.10-11.el10_0.2, ruby-default-gems-3.3.10-11.el10_0.2 +20
    • Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) ruby-doc-3.3.10-11.el10_0.2
  • RHSA-2026:33721 Released 2026-06-30 · Red Hat rating Important
    Red Hat Hardened Images RPMs Security Update
    • Red Hat Hardened Images ruby3.3-3.3.10-23.2.hum1@aarch64, ruby3.3-3.3.10-23.2.hum1@src, ruby3.3-3.3.10-23.2.hum1@x86_64 +46
  • RHSA-2026:33577 Released 2026-06-30 · Red Hat rating Important
    ruby:4.0 security update
    • Red Hat Enterprise Linux AppStream (v. 9) ruby-4.0.3-33.module+el9.8.0+24428+77f1d00a.aarch64::ruby:4.0, ruby-4.0.3-33.module+el9.8.0+24428+77f1d00a.i686::ruby:4.0, ruby-4.0.3-33.module+el9.8.0+24428+77f1d00a.ppc64le::ruby:4.0 +47
  • RHSA-2026:33576 Released 2026-06-30 · Red Hat rating Important
    ruby:3.3 security update
    • Red Hat Enterprise Linux AppStream (v. 9) ruby-3.3.10-7.module+el9.8.0+24406+8975e57f.aarch64::ruby:3.3, ruby-3.3.10-7.module+el9.8.0+24406+8975e57f.i686::ruby:3.3, ruby-3.3.10-7.module+el9.8.0+24406+8975e57f.ppc64le::ruby:3.3 +47
  • RHSA-2026:33515 Released 2026-06-30 · Red Hat rating Important
    ruby:3.3 security update
    • Red Hat Enterprise Linux AppStream (v. 8) ruby-3.3.10-7.module+el8.10.0+24407+4a33a056.aarch64::ruby:3.3, ruby-3.3.10-7.module+el8.10.0+24407+4a33a056.i686::ruby:3.3, ruby-3.3.10-7.module+el8.10.0+24407+4a33a056.ppc64le::ruby:3.3 +47
  • RHSA-2026:33565 Released 2026-06-30 · Red Hat rating Important
    ruby security update
    • Red Hat Enterprise Linux AppStream (v. 10) ruby-3.3.10-13.el10_2, ruby-bundled-gems-3.3.10-13.el10_2, ruby-default-gems-3.3.10-13.el10_2 +20
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) ruby-doc-3.3.10-13.el10_2
  • RHSA-2026:33540 Released 2026-06-30 · Red Hat rating Important
    ruby4.0 security update
    • Red Hat Enterprise Linux AppStream (v. 10) ruby4.0-4.0.3-35.el10_2, ruby4.0-devel-4.0.3-35.el10_2, ruby4.0-rubygem-mysql2-0.5.7-35.el10_2 +1
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) ruby4.0-doc-4.0.3-35.el10_2
  • RHSA-2026:33552 Released 2026-06-30 · Red Hat rating Important
    Red Hat Hardened Images RPMs Security Update
    • Red Hat Hardened Images ruby3.4-3.4.8-31.2.hum1@aarch64, ruby3.4-3.4.8-31.2.hum1@src, ruby3.4-3.4.8-31.2.hum1@x86_64 +46
  • RHSA-2026:33551 Released 2026-06-30 · Red Hat rating Important
    Red Hat Hardened Images RPMs Security Update
    • Red Hat Hardened Images ruby4.0-4.0.0-33.4.hum1@aarch64, ruby4.0-4.0.0-33.4.hum1@src, ruby4.0-4.0.0-33.4.hum1@x86_64 +46

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux AppStream (v. 10)Fixed RHSA-2026:33540, RHSA-2026:33565
Red Hat Enterprise Linux AppStream (v. 8)Fixed RHSA-2026:33515
Red Hat Enterprise Linux AppStream (v. 9)Fixed RHSA-2026:33576, RHSA-2026:33577
Red Hat Enterprise Linux AppStream E4S (v.9.4)Fixed RHSA-2026:36099
Red Hat Enterprise Linux AppStream EUS (v. 10.0)Fixed RHSA-2026:35895
Red Hat Enterprise Linux AppStream EUS (v.9.6)Fixed RHSA-2026:37238
Red Hat Enterprise Linux CodeReady Linux Builder (v. 10)Fixed RHSA-2026:33540, RHSA-2026:33565
Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0)Fixed RHSA-2026:35895
Red Hat Hardened ImagesFixed RHSA-2026:33551, RHSA-2026:33552, RHSA-2026:33721, RHSA-2026:38694
Not affected: 1 product
  • Red Hat 3scale API Management Platform 2

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-42245
  2. 2026-10-03 Alias added: GHSA-q2mw-fvj9-vvcw
  3. 2026-10-25 EPSS moved to the below the 50th percentile
  4. 2026-11-06 Affected versions changed · Red Hat

References

Patch 3

Advisory 2

Other 5

  • TI-2026-30563 net-imap vulnerable to STARTTLS stripping via invalid response timing CVSS 4.0HIGH 7.6
  • TI-2026-30574 net-imap: Command Injection via unvalidated Symbol inputs CVSS 4.0MEDIUM 5.8
  • TI-2026-30572 net-imap: Denial of service via high iteration count for `SCRAM-*` authentication CVSS 4.0MEDIUM 6.0
  • TI-2025-28441 net-imap rubygem vulnerable to possible DoS by memory exhaustion CVSS 4.0MEDIUM 6.0
  • TI-2026-30573 net-imap: Command Injection via "raw" arguments to multiple commands CVSS 4.0MEDIUM 5.8

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences