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CVE-2026-42258

📛 CVE Title

net-imap: Command Injection via unvalidated Symbol inputs

⬇ Download JSON ⚠ View as Threat

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, symbol arguments to commands are vulnerable to a CRLF Injection / IMAP Command injection via Symbol arguments passed to IMAP commands. This issue has been patched in versions 0.4.24, 0.5.14, and 0.6.4.

Overview

State
PUBLISHED
Assigner (CNA)
GitHub_M
CVSS severity
MEDIUM
CVSS score
CVSS 5.8 / 10 5.8 5.8 / 10
CVSS vector
CVSS:4.0/AV:L/AC:H/AT:P/PR:N/UI:P/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N
Effective score
5.8 / 10 MEDIUM source: CNA overview
CWE(s)
CWE-77, CWE-93
Reserved
2026-04-26
Published
2026-05-09 21:40 UTC
Last updated
2026-05-11 16:57 UTC
Source
https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/42xxx/CVE-2026-42258.json
Linked Threat
CVE-2026-42258 — CVE-2026-42258

NVD triage scoring NVD CVE 2.0

Layer NVD adds on top of the CNA's CVE record — published / last-modified timestamps, exploitability / impact subscores, and the FIRST.org EPSS probability that this CVE will be exploited in the wild in the next 30 days.

NVD published
2026-05-09 20:16:28 UTC
NVD last modified
2026-05-18 18:02:35 UTC
NVD CVSS v3.1
CVSS 9.8 / 10 9.8 9.8 / 10 CRITICAL source: nvd@nist.gov
NVD CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Exploitability subscore
3.9 / 10
Impact subscore
5.9 / 10
EPSS score
0.0009 (probability of exploitation in next 30 days)
EPSS percentile
25.64% vs all CVEs — higher = more likely to be exploited, as of 2026-05-24

NVD / KEV / EPSS data refreshed 2026-05-25 09:36 UTC. Re-run the 🛰 Backfill from NVD button above to refresh.

European Union Vulnerability Database ENISA EUVD

ENISA's official EU repository for curated vulnerability intelligence. Carries a separate identifier (EUVD-YYYY-NNNN) and frequently exposes an earlier-published description + CVSS than NVD does.

EUVD ID
EUVD-2026-28927
Assigner
GitHub_M
Published
May 9, 2026, 7:40:49 PM
Updated
May 11, 2026, 2:57:24 PM
EUVD base score (CVSS 4.0)
5.8 / 10
CVSS:4.0/AV:L/AC:H/AT:P/PR:N/UI:P/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N
EUVD-reported EPSS
0.0900
Vendors
Ruby
Products
net-imap (0.5.0, < 0.5.14)
net-imap (0.6.0, < 0.6.4)
net-imap (< 0.4.24)
Aliases
GHSA-75xq-5h9v-w6px

ENISA 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, symbol arguments to commands are vulnerable to a CRLF Injection / IMAP Command injection via Symbol arguments passed to IMAP commands. This issue has been patched in versions 0.4.24, 0.5.14, and 0.6.4.

EUVD references (4)

Microsoft Security Response Center MSRC

Microsoft's vendor-authoritative record from the Security Update Guide — its own CVSS score, impact, severity rating, exploit assessment, and KB-article fixes. Refreshed 2026-08-15 03:01 UTC (source: CVRF).

MS severity
Moderate
Release
2026-May

Affected products (1)
VendorProductVersionsPlatforms
ruby net-imap < 0.4.24 (affected), >= 0.5.0, < 0.5.14 (affected), >= 0.6.0, < 0.6.4 (affected) —

Affected products — CPE 2.3 (1) NVD

NVD's normalized CPE 2.3 matchers, used by vendor tools (vulnerability scanners, asset managers) for automated detection. Compare with the CNA's free-text "Affected products" section above.

  • cpe:2.3:a:ruby-lang:net\:\:imap:*:*:*:*:*:ruby:*:*

Vendor references (4)

References embedded in the original CVE record by the assigning CNA.

MITRE references (4) cveawg.mitre.org

Pulled from MITRE's CVE Services API by the 🛰 Backfill from MITRE button.

Web references (4)

DuckDuckGo results ranked by threat-intel / vendor advisory domains. Generated by the 🔎 Find references (web) button above — same flow as the Remediations search.

NVD-tagged references (4)

Reference list NVD curates from the CNA record, vendor advisories, and third-party reports. The tag chips below are NVD's analyst-assigned categories.

Remediations (18)

Remediations are stored against the linked Threat row; the list below is deduplicated across both pages.

  • Patch Management Best Practices for 2025 | RSI Security
    web:blog.rsisecurity.com

    The Vulnerability Management Lifecycle Patch management is a vital component of the broader vulnerability management lifecycle, which includes: Discovery: Identify all systems and assets. Assessment: Evaluate severity and exploitability. Prioritization: Align risk levels with business impact. Remediation : Apply patches or compensating controls. Verification: Confirm successful patch deployment ...

    2026-05-23 21:03 UTC
  • CISA Warns of Exploited Microsoft Defender 0-Day Flaws
    web:cyberpress.org

    The U.S. Cybersecurity and Infrastructure Security Agency (CISA) has added two actively exploited Microsoft Defender vulnerabilities to its Known Exploited Vulnerabilities (KEV) catalog, issuing an urgent remediation directive for federal agencies with a due date of June 3, 2026 .

    2026-05-23 21:03 UTC
  • Nvd - Cve-2026-42258
    web:nvd.nist.gov

    An official website of the United States government Here's how you know

    2026-05-23 21:03 UTC
  • Security Update Guide - Microsoft
    web:portal.msrc.microsoft.com

    The Security Update Guide provides information on the latest Microsoft security updates, helping users understand and address potential vulnerabilities effectively.

    2026-05-23 21:03 UTC
  • Fortinet Releases Guidance to Address Ongoing Exploitation of ... - CISA
    web:www.cisa.gov

    Fortinet Releases Guidance to Address Ongoing Exploitation of Authentication Bypass Vulnerability CVE - 2026 -24858

    2026-05-23 21:03 UTC
  • February's Patch Tuesday release fixes 59 flaws ... - Computerworld
    web:www.computerworld.com

    Each month, the team at Readiness analyzes the latest Patch Tuesday updates from Microsoft and provides detailed, actionable testing guidance. The company's Patch Tuesday release for February ...

    2026-05-23 21:03 UTC
  • April 2026 Patch Tuesday: Updates and Analysis | CrowdStrike
    web:www.crowdstrike.com

    Microsoft's April 2026 Patch Tuesday addresses 164 CVEs , featuring 8 Critical vulnerabilities, one exploited zero-day, and one disclosed zero-day.

    2026-05-23 21:03 UTC
  • What To Do If You Can't Patch A Software Vulnerability - Forbes
    web:www.forbes.com

    Mitigation Measures To Take If Patching Isn't Possible Assuming a patch can't be promptly applied, what can be done to mitigate risk? There are several important measures to keep in mind:

    2026-05-23 21:03 UTC
  • Oracle Critical Patch Update Advisory - April 2026
    web:www.oracle.com

    This Critical Patch Update contains 481 new security patches across the product families listed below. Please note that an MOS note summarizing the content of this Critical Patch Update and other Oracle Software Security Assurance activities is located at April 2026 Critical Patch Update: Executive Summary and Analysis.

    2026-05-23 21:03 UTC
  • Patch Tuesday May 2026: Security Updates & CVE Analysis
    web:zecurit.com

    Get the complete breakdown of Microsoft's May 2026 Patch Tuesday. We analyze the latest security updates and all critical CVEs .

    2026-05-23 21:03 UTC
  • Mitigate RedSun Zero-Day Without A Patch | Qualys
    web:blog.qualys.com

    Key Takeaways RedSun is a critical zero-day vulnerability in Microsoft Defender that allows low-privileged users to gain SYSTEM access No patch is currently available, leaving all Defender-enabled Windows systems potentially exposed Qualys VMDR detects affected assets instantly (QID 92382) TruRisk™ Eliminate enables immediate mitigation , removing exploitability without waiting for a fix ...

    2026-05-26 02:50 UTC
  • Security Advisory Bulletin 064 | Ubiquiti Community
    web:community.ui.com

    Published: May 21, 2026 Updated: May 22, 2026 Version: 1.1 Revision: 1.1 Summary 1 of 5 A malicious actor with access to the network and high privileges could exploit an Improper Input Validation vulnerability found in UniFi OS devices to execute a Command Injection. Affected Products: UniFi OS Server (Version 5.0.6 and earlier) Mitigation : Update your UniFi OS Server to Version 5.0.8 or later ...

    2026-05-26 02:50 UTC
  • Microsoft April 2026 Patch Tuesday Fixes 168 Flaws, Includes Actively ...
    web:cyberpress.org

    Microsoft has released its April 2026 Patch Tuesday updates, fixing 168 vulnerabilities across Windows, cloud, and application products, including one actively exploited zero-day in Microsoft SharePoint Server.

    2026-05-26 02:50 UTC
  • Current Common Vulnerabilities and Exposures - Feedly
    web:feedly.com

    Welcome to Feedly CVEs — Research critical vulnerabilities ( CVEs ) with all the real-time and historical information you need to assess the risk to your organization. This free resource uses Feedly's AI to synthesize and analyze vulnerability information from across the web, including estimating CVSS scores up to 3 days before it's reported to the NVD.

    2026-05-26 02:50 UTC
  • Security Update Guide - Microsoft Security Response Center
    web:msrc.microsoft.com

    Security Update Guide - Microsoft Security Response Center

    2026-05-26 02:50 UTC
  • Critical Patches Issued for Microsoft Products, May 12, 2026
    web:www.cisecurity.org

    <p>Multiple vulnerabilities have been discovered in Microsoft products, the most severe of which could allow for remote code execution. Successful exploitation of the most severe of these vulnerabilities could result in an attacker gaining the same privileges as the logged-on user. Depending on the privileges associated with the user, an attacker could then install programs; view, change, or ...

    2026-05-26 02:50 UTC
  • Microsoft is working on a patch for 'YellowKey ... - Computerworld
    web:www.computerworld.com

    Microsoft says it is considering a patch for a zero-day vulnerability, dubbed YellowKey, that allows attackers with access to a Windows device to bypass Bitlocker encryption protection and read ...

    2026-05-26 02:50 UTC
  • CVE: Common Vulnerabilities and Exposures
    web:www.cve.org

    At cve .org, we provide the authoritative reference method for publicly known information-security vulnerabilities and exposures

    2026-05-26 02:50 UTC

AI Forensic Analysis

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Raw JSON

The full cvelistV5 record. Download as CVE-2026-42258.json.

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