RHSA-2026:50773 - Security Advisory

Topic

An update for ruby4.0 is now available for Red Hat Enterprise Linux 10.

Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.

Description

Ruby is the interpreted scripting language for quick and easy object-oriented programming. It has many features to process text files and to do system management tasks (as in Perl). It is simple, straight-forward, and extensible.

Security Fix(es):

• zlib: zlib: Memory corruption via buffer overflow in Zlib::GzipReader (CVE-2026-27820)
• net-imap: Net::IMAP: Arbitrary IMAP command injection via CRLF sequences in unvalidated input (CVE-2026-42257)
• ruby/net-imap: ruby: Net::IMAP: Denial of Service via large iteration count in SCRAM authentication (CVE-2026-42256)
• net-imap: Net::IMAP: Command injection via non-synchronizing literals (CVE-2026-47240)
• net-imap: Net::IMAP: Arbitrary IMAP command injection due to improper input validation (CVE-2026-47242)
• net-imap: rubygem-net-imap: Net::IMAP: Denial of Service via malformed command input (CVE-2026-47241)

Bug Fix(es) and Enhancement(s):

• ruby4.0: Rebase to the latest Ruby 4.0 release [rhel-10.2.z] (JIRA:RHEL-211310)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Solution

For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

Affected Products

• Red Hat Enterprise Linux for x86_64 10 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 10.2 x86_64
• Red Hat Enterprise Linux for IBM z Systems 10 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 10.2 s390x
• Red Hat Enterprise Linux for Power, little endian 10 ppc64le
• Red Hat Enterprise Linux for Power, little endian - Extended Update Support 10.2 ppc64le
• Red Hat Enterprise Linux for ARM 64 10 aarch64
• Red Hat Enterprise Linux for ARM 64 - Extended Update Support 10.2 aarch64
• Red Hat CodeReady Linux Builder for x86_64 10 x86_64
• Red Hat CodeReady Linux Builder for Power, little endian 10 ppc64le
• Red Hat CodeReady Linux Builder for ARM 64 10 aarch64
• Red Hat CodeReady Linux Builder for IBM z Systems 10 s390x
• Red Hat CodeReady Linux Builder for x86_64 - Extended Update Support 10.2 x86_64
• Red Hat CodeReady Linux Builder for Power, little endian - Extended Update Support 10.2 ppc64le
• Red Hat CodeReady Linux Builder for IBM z Systems - Extended Update Support 10.2 s390x
• Red Hat CodeReady Linux Builder for ARM 64 - Extended Update Support 10.2 aarch64
• Red Hat Enterprise Linux for ARM 64 - 4 years of updates 10.2 aarch64
• Red Hat Enterprise Linux for IBM z Systems - 4 years of updates 10.2 s390x
• Red Hat Enterprise Linux for Power, little endian - 4 years of support 10.2 ppc64le
• Red Hat Enterprise Linux for x86_64 - 4 years of updates 10.2 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Life Cycle 10.2 x86_64
• Red Hat Enterprise Linux for ARM 64 - Extended Life Cycle 10.2 aarch64
• Red Hat Enterprise Linux for Power, little endian - Extended Life Cycle 10.2 ppc64le
• Red Hat Enterprise Linux for IBM z Systems - Extended Life Cycle 10.2 s390x

Fixes

• BZ - 2459002 - CVE-2026-27820 zlib: zlib: Memory corruption via buffer overflow in Zlib::GzipReader
• BZ - 2468494 - CVE-2026-42257 net-imap: Net::IMAP: Arbitrary IMAP command injection via CRLF sequences in unvalidated input
• BZ - 2468500 - CVE-2026-42256 ruby/net-imap: ruby: Net::IMAP: Denial of Service via large iteration count in SCRAM authentication
• BZ - 2491519 - CVE-2026-47240 net-imap: Net::IMAP: Command injection via non-synchronizing literals
• BZ - 2491523 - CVE-2026-47241 net-imap: rubygem-net-imap: Net::IMAP: Denial of Service via malformed command input

CVEs

• CVE-2026-27820
• CVE-2026-42256
• CVE-2026-42257
• CVE-2026-47240
• CVE-2026-47241
• CVE-2026-47242

References

• https://access.redhat.com/security/updates/classification/#important