CyberSecBulletin
CVE-2026-42246NVD status: Modified

net-imap: Missing Report of Error Condition

Published Updated By the CyberSecBulletin desk

CVE-2026-42246 is a high-severity missing report of error condition vulnerability in net-imap from Ruby, with a CVSS 3.1 base score of 7.4 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected net-imap versions: < 0.3.10; >= 0.4.0, < 0.4.24; >= 0.5.0, < 0.5.14, and others listed below. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.31% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Net to 0.3.10 or 0.4.24 or 0.5.14 or 0.6.4, whichever matches your release line, or a later version.
  2. Read the advisory on github.com for workarounds and exact fixed builds.
  3. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
Rubynet-imap< 0.3.10; >= 0.4.0, < 0.4.24; >= 0.5.0, < 0.5.14; >= 0.6.0, < 0.6.4Not stated
Red HatRed Hat Enterprise Linux 10Not specified in the recordNot stated
Red HatRed Hat Enterprise Linux 10.0 Extended Update SupportNot specified in the recordNot stated
Red HatRed Hat Enterprise Linux 7 Extended Lifecycle SupportNot specified in the recordNot stated
Red HatRed Hat Enterprise Linux 8Not specified in the recordNot stated
Red HatRed Hat Enterprise Linux 8.4 Advanced Mission Critical Update SupportNot specified in the recordNot stated
Red HatRed Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-OnNot specified in the recordNot stated
Red HatRed Hat Enterprise Linux 8.6 Advanced Mission Critical Update SupportNot specified in the recordNot stated
Red HatRed Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-OnNot specified in the recordNot stated
Red HatRed Hat Enterprise Linux 8.8 Telecommunications Update ServiceNot specified in the recordNot stated
Red HatRed Hat Enterprise Linux 8.8 Update Services for SAP SolutionsNot specified in the recordNot stated
Red HatRed Hat Enterprise Linux 9Not specified in the recordNot stated
Red HatRed Hat Enterprise Linux 9.2 Update Services for SAP SolutionsNot specified in the recordNot stated
Red HatRed Hat Enterprise Linux 9.4 Update Services for SAP SolutionsNot specified in the recordNot stated
Red HatRed Hat Enterprise Linux 9.6 Extended Update SupportNot specified in the recordNot stated
Red HatRed Hat Hardened ImagesNot specified in the recordNot stated
Red HatRed Hat 3scale API Management Platform 2Not specified in the recordNot stated
Red HatRed Hat Enterprise Linux 6Not specified in the recordNot stated
Red HatRed Hat OpenShift Container Platform 4Not specified in the recordNot stated
Ruby-langNetbefore 0.3.10; 0.4.0 up to, but not including, 0.4.24; 0.5.0 up to, but not including, 0.5.14; 0.6.0 up to, but not including, 0.6.40.3.10, 0.4.24, 0.5.14, 0.6.4

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
HighSuccess depends on conditions outside the attacker's control.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
NoneAvailability is not affected.

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 4.07.6HighCNA (github.com)
CVSS 3.17.4HighNVD
CVSS 3.17.4HighCNA

Official description

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.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Missing Report of Error Condition

The product encounters an error but does not provide a status code or return value to indicate that an error has occurred.

More Missing Report of Error Condition vulnerabilities (CWE-392)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in net-imap

All net-imap vulnerabilities

Recent Missing Report of Error Condition vulnerabilities

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