CVE•Published 2026-05-09•Modified 2026-07-24•1 article on news•4 live references•NVD data

CVE-2026-42257Ruby-lang · Net\

Vulnerability data via NVD (ingested)

CVSS v3.1

9.8

CRITICAL

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

EPSS percentile

Exploit Prediction Scoring System · top 65% of all CVEs

Weaknesses (CWE)

CWE-77Improper Neutralization of Special Elements used in a Command ('Command Injection')CWE-93Improper Neutralization of CRLF Sequences ('CRLF Injection')

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, several Net::IMAP commands accept a raw string argument that is sent to the server without validation or escaping. If this string is derived from user-controlled input, it may contain contain CRLF sequences, which an attacker can use to inject arbitrary IMAP commands. This issue has been patched in versions 0.4.24, 0.5.14, and 0.6.4.

Timeline

Published 2026-05-09

Modified 2026-07-24

External references

NVD MITRE Exploit-DB VulnCheck

Search for exposed instances

Shodan + Censys queries derived from NVD's CPE data. The vuln tag catches assets Shodan has explicitly linked to this CVE; the product / banner fingerprints find exposed instances even when the vuln tag was never applied (which is common). Live host counts are a Premium feature.

Shodan · vuln tag

vuln:CVE-2026-42257

Hosts Shodan has explicitly fingerprinted as vulnerable.

Shodan · product + version

product:"Ruby-lang Net\" version:"\"

Version-pinned fingerprint from NVD's first vulnerable CPE.

Shodan · banner/body mention

http.html:"Net\"

HTTP body or banner mentions "Net\" — catches deploys Shodan didn't identify as a product.

More intel sources (5)

Shodan report

vuln:CVE-2026-42257