CVE-2026-42256 Vulnerability Analysis & Exploit Details

CVE-2026-42256
Vulnerability Scoring

6.5
/10
High Risk

If left unpatched, CVE-2026-42256 could lead to major system disruptions or data loss.

Attack Complexity Details

  • Attack Complexity: Low
    Exploits can be performed without significant complexity or special conditions.
  • Attack Vector: Network
    Vulnerability is exploitable over a network without physical access.
  • Privileges Required: None
    No privileges are required for exploitation.
  • Scope: Unchanged
    Exploit remains within the originally vulnerable component.
  • User Interaction: Required
    User interaction is necessary for successful exploitation.

CVE-2026-42256 Details

Status: Analyzed

Last updated: 🕕 18 May 2026, 18:06 UTC
Originally published on: 🕗 09 May 2026, 20:16 UTC

Time between publication and last update: 8 days

CVSS Release: version 3

CVSS3 Source

nvd@nist.gov

CVSS3 Type

Primary

CVSS3 Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

CVE-2026-42256 Vulnerability Summary

CVE-2026-42256: Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. From versions 0.4.0 to before 0.4.24, 0.5.0 to before 0.5.14, and 0.6.0 to before 0.6.4, when authenticating a connection with SCRAM-SHA1 or SCRAM-SHA256, a hostile server can perform a computational denial-of-service attack on the client process by sending a big iteration count value. This issue has been patched in versions 0.4.24, 0.5.14, and 0.6.4.

Assessing the Risk of CVE-2026-42256

Access Complexity Graph

The exploitability of CVE-2026-42256 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).

Exploitability Analysis for CVE-2026-42256

With low attack complexity and no required privileges, CVE-2026-42256 is an easy target for cybercriminals. Organizations should prioritize immediate mitigation measures to prevent unauthorized access and data breaches.

Understanding AC and PR

A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.

Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.

Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.

CVSS Score Breakdown Chart

Above is the CVSS Sub-score Breakdown for CVE-2026-42256, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.

CIA Impact Analysis

Below is the Impact Analysis for CVE-2026-42256, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.

  • Confidentiality: None
    CVE-2026-42256 has no significant impact on data confidentiality.
  • Integrity: None
    CVE-2026-42256 poses no threat to data integrity.
  • Availability: High
    CVE-2026-42256 can disrupt system operations, potentially causing complete denial of service (DoS).

CVE-2026-42256 References

External References

CWE Common Weakness Enumeration

CWE-1322

CAPEC Common Attack Pattern Enumeration and Classification

  • Forced Deadlock CAPEC-25 The adversary triggers and exploits a deadlock condition in the target software to cause a denial of service. A deadlock can occur when two or more competing actions are waiting for each other to finish, and thus neither ever does. Deadlock conditions can be difficult to detect.

Vulnerable Configurations

  • cpe:2.3:a:ruby-lang:net\:\:imap:0.4.0:*:*:*:*:ruby:*:*
    cpe:2.3:a:ruby-lang:net\:\:imap:0.4.0:*:*:*:*:ruby:*:*
  • cpe:2.3:a:ruby-lang:net\:\:imap:0.4.1:*:*:*:*:ruby:*:*
    cpe:2.3:a:ruby-lang:net\:\:imap:0.4.1:*:*:*:*:ruby:*:*
  • cpe:2.3:a:ruby-lang:net\:\:imap:0.4.2:*:*:*:*:ruby:*:*
    cpe:2.3:a:ruby-lang:net\:\:imap:0.4.2:*:*:*:*:ruby:*:*
  • cpe:2.3:a:ruby-lang:net\:\:imap:0.4.3:*:*:*:*:ruby:*:*
    cpe:2.3:a:ruby-lang:net\:\:imap:0.4.3:*:*:*:*:ruby:*:*
  • cpe:2.3:a:ruby-lang:net\:\:imap:0.4.4:*:*:*:*:ruby:*:*
    cpe:2.3:a:ruby-lang:net\:\:imap:0.4.4:*:*:*:*:ruby:*:*
  • cpe:2.3:a:ruby-lang:net\:\:imap:0.4.5:*:*:*:*:ruby:*:*
    cpe:2.3:a:ruby-lang:net\:\:imap:0.4.5:*:*:*:*:ruby:*:*
  • cpe:2.3:a:ruby-lang:net\:\:imap:0.4.6:*:*:*:*:ruby:*:*
    cpe:2.3:a:ruby-lang:net\:\:imap:0.4.6:*:*:*:*:ruby:*:*
  • cpe:2.3:a:ruby-lang:net\:\:imap:0.4.7:*:*:*:*:ruby:*:*
    cpe:2.3:a:ruby-lang:net\:\:imap:0.4.7:*:*:*:*:ruby:*:*
  • cpe:2.3:a:ruby-lang:net\:\:imap:0.4.8:*:*:*:*:ruby:*:*
    cpe:2.3:a:ruby-lang:net\:\:imap:0.4.8:*:*:*:*:ruby:*:*
  • cpe:2.3:a:ruby-lang:net\:\:imap:0.4.9:*:*:*:*:ruby:*:*
    cpe:2.3:a:ruby-lang:net\:\:imap:0.4.9:*:*:*:*:ruby:*:*
  • cpe:2.3:a:ruby-lang:net\:\:imap:0.4.9.1:*:*:*:*:ruby:*:*
    cpe:2.3:a:ruby-lang:net\:\:imap:0.4.9.1:*:*:*:*:ruby:*:*
  • cpe:2.3:a:ruby-lang:net\:\:imap:0.4.10:*:*:*:*:ruby:*:*
    cpe:2.3:a:ruby-lang:net\:\:imap:0.4.10:*:*:*:*:ruby:*:*
  • cpe:2.3:a:ruby-lang:net\:\:imap:0.4.11:*:*:*:*:ruby:*:*
    cpe:2.3:a:ruby-lang:net\:\:imap:0.4.11:*:*:*:*:ruby:*:*
  • cpe:2.3:a:ruby-lang:net\:\:imap:0.4.12:*:*:*:*:ruby:*:*
    cpe:2.3:a:ruby-lang:net\:\:imap:0.4.12:*:*:*:*:ruby:*:*
  • cpe:2.3:a:ruby-lang:net\:\:imap:0.4.13:*:*:*:*:ruby:*:*
    cpe:2.3:a:ruby-lang:net\:\:imap:0.4.13:*:*:*:*:ruby:*:*
  • cpe:2.3:a:ruby-lang:net\:\:imap:0.4.14:*:*:*:*:ruby:*:*
    cpe:2.3:a:ruby-lang:net\:\:imap:0.4.14:*:*:*:*:ruby:*:*
  • cpe:2.3:a:ruby-lang:net\:\:imap:0.4.15:*:*:*:*:ruby:*:*
    cpe:2.3:a:ruby-lang:net\:\:imap:0.4.15:*:*:*:*:ruby:*:*
  • cpe:2.3:a:ruby-lang:net\:\:imap:0.4.16:*:*:*:*:ruby:*:*
    cpe:2.3:a:ruby-lang:net\:\:imap:0.4.16:*:*:*:*:ruby:*:*
  • cpe:2.3:a:ruby-lang:net\:\:imap:0.4.17:*:*:*:*:ruby:*:*
    cpe:2.3:a:ruby-lang:net\:\:imap:0.4.17:*:*:*:*:ruby:*:*
  • cpe:2.3:a:ruby-lang:net\:\:imap:0.4.18:*:*:*:*:ruby:*:*
    cpe:2.3:a:ruby-lang:net\:\:imap:0.4.18:*:*:*:*:ruby:*:*
  • cpe:2.3:a:ruby-lang:net\:\:imap:0.4.19:*:*:*:*:ruby:*:*
    cpe:2.3:a:ruby-lang:net\:\:imap:0.4.19:*:*:*:*:ruby:*:*
  • cpe:2.3:a:ruby-lang:net\:\:imap:0.4.20:*:*:*:*:ruby:*:*
    cpe:2.3:a:ruby-lang:net\:\:imap:0.4.20:*:*:*:*:ruby:*:*
  • cpe:2.3:a:ruby-lang:net\:\:imap:0.4.21:*:*:*:*:ruby:*:*
    cpe:2.3:a:ruby-lang:net\:\:imap:0.4.21:*:*:*:*:ruby:*:*
  • cpe:2.3:a:ruby-lang:net\:\:imap:0.5.0:*:*:*:*:ruby:*:*
    cpe:2.3:a:ruby-lang:net\:\:imap:0.5.0:*:*:*:*:ruby:*:*
  • cpe:2.3:a:ruby-lang:net\:\:imap:0.5.1:*:*:*:*:ruby:*:*
    cpe:2.3:a:ruby-lang:net\:\:imap:0.5.1:*:*:*:*:ruby:*:*
  • cpe:2.3:a:ruby-lang:net\:\:imap:0.5.2:*:*:*:*:ruby:*:*
    cpe:2.3:a:ruby-lang:net\:\:imap:0.5.2:*:*:*:*:ruby:*:*
  • cpe:2.3:a:ruby-lang:net\:\:imap:0.5.3:*:*:*:*:ruby:*:*
    cpe:2.3:a:ruby-lang:net\:\:imap:0.5.3:*:*:*:*:ruby:*:*
  • cpe:2.3:a:ruby-lang:net\:\:imap:0.5.4:*:*:*:*:ruby:*:*
    cpe:2.3:a:ruby-lang:net\:\:imap:0.5.4:*:*:*:*:ruby:*:*
  • cpe:2.3:a:ruby-lang:net\:\:imap:0.5.5:*:*:*:*:ruby:*:*
    cpe:2.3:a:ruby-lang:net\:\:imap:0.5.5:*:*:*:*:ruby:*:*
  • cpe:2.3:a:ruby-lang:net\:\:imap:0.5.6:*:*:*:*:ruby:*:*
    cpe:2.3:a:ruby-lang:net\:\:imap:0.5.6:*:*:*:*:ruby:*:*
  • cpe:2.3:a:ruby-lang:net\:\:imap:0.5.7:*:*:*:*:ruby:*:*
    cpe:2.3:a:ruby-lang:net\:\:imap:0.5.7:*:*:*:*:ruby:*:*
  • cpe:2.3:a:ruby-lang:net\:\:imap:0.5.8:*:*:*:*:ruby:*:*
    cpe:2.3:a:ruby-lang:net\:\:imap:0.5.8:*:*:*:*:ruby:*:*

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