CVE•Published 2026-05-09•Modified 2026-07-24•0 articles on news•4 live references•NVD data

CVE-2026-42256Ruby-lang · Net\

Vulnerability data via NVD (ingested)

CVSS v3.1

6.5

MEDIUM

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

EPSS percentile

Exploit Prediction Scoring System · top 78% of all CVEs

Weaknesses (CWE)

CWE-770Allocation of Resources Without Limits or Throttling CWE-1322Use of Blocking Code in Single-threaded, Non-blocking Context

Description

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.

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).

Shodan · vuln tag0 hosts

vuln:CVE-2026-42256

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-2026-42256