CRLF Injection Affecting ruby4.0-default-gems package, versions <0:4.0.0-33.4.hum1


Severity

Recommended
0.0
medium
0
10

Based on Red Hat Enterprise Linux security rating.

Threat Intelligence

EPSS
0.49% (39th percentile)

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  • Snyk IDSNYK-RHEL10-RUBY40DEFAULTGEMS-17987429
  • published16 Jul 2026
  • disclosed22 Jun 2026

Introduced: 22 Jun 2026

CVE-2026-47240  (opens in a new tab)
CWE-93  (opens in a new tab)

How to fix?

Upgrade RHEL:10 ruby4.0-default-gems to version 0:4.0.0-33.4.hum1 or higher.
This issue was patched in RHSA-2026:33551.

NVD Description

Note: Versions mentioned in the description apply only to the upstream ruby4.0-default-gems package and not the ruby4.0-default-gems package as distributed by RHEL. See How to fix? for RHEL:10 relevant fixed versions and status.

Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. Prior to 0.6.5 and 0.5.15, several Net::IMAP commands accept a "raw data" argument that is sent verbatim after validation to prevent command injection. However, if a server does not support non-synchronizing literals, it may still be possible to inject arbitrary IMAP commands inside non-synchronizing literals. A server without support for non-synchronizing literals may interpret the "+}\r\n" as the end of a malformed command line and respond with a tagged BAD. In that case, the contents of the literal will be interpreted as one or more new pipelined commands, allowing a CRLF command injection attack to succeed. This affects criteria for #search and #uid_search; search_keys for #sort, #thread, #uid_sort, and #uid_thread; and attr for #fetch and #uid_fetch. This vulnerability is fixed in 0.6.5 and 0.5.15.

CVSS Base Scores

version 3.1