Affected: AlmaLinux:8: ruby, AlmaLinux:8: ruby-bundled-gems, AlmaLinux:8: ruby-default-gems, AlmaLinux:8: ruby-devel, AlmaLinux:8: ruby-doc, AlmaLinux:8: ruby-libs, AlmaLinux:8: rubygem-abrt, AlmaLinux:8: rubygem-abrt-doc, AlmaLinux:8: rubygem-bigdecimal, AlmaLinux:8: rubygem-bundler and 20 more

Ruby is an extensible, interpreted, object-oriented, scripting language. It has features to process text files and to perform system management tasks.

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):

* ruby:3.3/ruby: Rebase to the latest Ruby 3.3 release [almalinux-8] (JIRA:AlmaLinux-170929)

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.

Affected: Alpaquita:stream: ruby-net-imap

Affected: Homebrew: imap-backup

### Summary

Several Net::IMAP commands accept a raw string argument which is only validated to prevent CRLF injection and then sent verbatim. If this string is derived from user-controlled input, an attacker can force the next command to be absorbed as a continuation of the first command. This will cause the first command to eventually fail, but also prevents it from returning until another command is sent (from another thread). That other command will not return until the connection is closed.

### Details

`Net::IMAP::RawData` was hardened in v0.6.4, v0.5.14, and v0.4.24 to reject string arguments that would smuggle an invalid literal-continuation marker onto the wire (CVE-2026-42257, GHSA-hm49-wcqc-g2xg). But the trailing-marker check uses an incorrect regex which does not match `{0}` or `{0+}`, so an attacker-controlled seach `criteria` or fetch `attr` string ending in `{0}` or `{0+}` passes validation and is sent verbatim. Since these arguments are sent as the last argument in the command, they will be followed by CRLF. Although the CRLF was intended to end the command, the server will interpret it as part of a literal prefix. This consumes the next command the client puts on the socket as additional arguments to the current command.

This affects the following command's arguments: * `criteria` for `#search` and `#uid_search` * `search_keys` for `#sort`, `#thread`, `#uid_sort`, and `#uid_thread` * `attr` for `#fetch` and `#uid_fetch`

The command which contained…

Affected: CleanStart: logstash-fips

Security vulnerability affects the logstash-fips package. This issue is resolved in later releases. See references for vulnerability details.

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 string argument which is only validated to prevent CRLF injection and then sent verbatim. If this string is derived from user-controlled input, an attacker can force the next command to be absorbed as a continuation of the first command. This will cause the first command to eventually fail, but also prevents it from returning until another command is sent (from another thread). That other command will not return until the connection is closed. This vulnerability is fixed in 0.6.5 and 0.5.15.

Affected: RubyGems: net-imap

### Summary

Several Net::IMAP commands accept a raw string argument which is only validated to prevent CRLF injection and then sent verbatim. If this string is derived from user-controlled input, an attacker can force the next command to be absorbed as a continuation of the first command. This will cause the first command to eventually fail, but also prevents it from returning until another command is sent (from another thread). That other command will not return until the connection is closed.

### Details

`Net::IMAP::RawData` was hardened in v0.6.4, v0.5.14, and v0.4.24 to reject string arguments that would smuggle an invalid literal-continuation marker onto the wire (CVE-2026-42257, GHSA-hm49-wcqc-g2xg). But the trailing-marker check uses an incorrect regex which does not match `{0}` or `{0+}`, so an attacker-controlled seach `criteria` or fetch `attr` string ending in `{0}` or `{0+}` passes validation and is sent verbatim. Since these arguments are sent as the last argument in the command, they will be followed by CRLF. Although the CRLF was intended to end the command, the server will interpret it as part of a literal prefix. This consumes the next command the client puts on the socket as additional arguments to the current command.

This affects the following command's arguments: * `criteria` for `#search` and `#uid_search` * `search_keys` for `#sort`, `#thread`, `#uid_sort`, and `#uid_thread` * `attr` for `#fetch` and `#uid_fetch`

The command which contained…

Affected: openEuler:22.03-LTS-SP4: ruby

Ruby is a fast and easy interpreted scripting language for object-oriented programming. It has many functions for processing text Files and perform system management tasks (such as Perl). Security Fix(es):

The attack vector is a potential Denial of Service (DoS). The vulnerability is caused by an insufficient check on the length of a decompressed domain name within a DNS packet.

An attacker can craft a malicious DNS packet containing a highly compressed domain name. When the resolv library parses such a packet, the name decompression process consumes a large amount of CPU resources, as the library does not limit the resulting length of the name.

This resource consumption can cause the application thread to become unresponsive, resulting in a Denial of Service condition.(CVE-2025-24294)

zlib is a Ruby interface for the zlib compression/decompression library. Versions 3.0.0 and below, 3.1.0, 3.1.1, 3.2.0 and 3.2.1 contain a buffer overflow vulnerability in the Zlib::GzipReader. The zstream_buffer_ungets function prepends caller-provided bytes ahead of previously produced output but fails to guarantee the backing Ruby string has enough capacity before the memmove shifts the existing data. This can lead to memory corruption when the buffer length exceeds capacity. This issue has been fixed in versions 3.0.1, 3.1.2 and 3.2.3.(CVE-2026-27820)

Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. Prior to 0.6.5 and 0.5.15, several Net::I…

Security update for ruby3.4

ruby: net-imap: Net::IMAP: Denial of Service via crafted IMAP responses net-imap: ruby: Net::IMAP: Information disclosure via man-in-the-middle attack bypassing TLS ruby/net-imap: ruby: Net::IMAP: Denial of Service via large iteration count in SCRAM authentication net-imap: Net::IMAP: Command injection via non-synchronizing literals net-imap: rubygem-net-imap: Net::IMAP: Denial of Service via malformed command input net-imap: Net::IMAP: Arbitrary IMAP command injection due to improper input validation

Affected: Rocky Linux:8: ruby, Rocky Linux:8: rubygem-abrt, Rocky Linux:8: rubygem-mysql2, Rocky Linux:8: rubygem-pg

Ruby is an extensible, interpreted, object-oriented, scripting language. It has features to process text files and to perform system management tasks.

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):

* ruby:3.3/ruby: Rebase to the latest Ruby 3.3 release [rhel-8] (JIRA:Rocky Linux-170929)

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.

Affected: Ubuntu:Pro:14.04:LTS: jruby, Ubuntu:Pro:16.04:LTS: ruby2.3, Ubuntu:16.04:LTS: jruby, Ubuntu:Pro:18.04:LTS: ruby2.5, Ubuntu:18.04:LTS: jruby, Ubuntu:Pro:20.04:LTS: ruby2.7, Ubuntu:20.04:LTS: jruby, Ubuntu:22.04:LTS: ruby3.0, Ubuntu:24.04:LTS: jruby, Ubuntu:24.04:LTS: ruby3.2 and 4 more

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 string argument which is only validated to prevent CRLF injection and then sent verbatim. If this string is derived from user-controlled input, an attacker can force the next command to be absorbed as a continuation of the first command. This will cause the first command to eventually fail, but also prevents it from returning until another command is sent (from another thread). That other command will not return until the connection is closed. This vulnerability is fixed in 0.6.5 and 0.5.15.

Ein Angreifer kann mehrere Schwachstellen in Ruby ausnutzen, um Informationen offenzulegen, um einen Denial of Service Angriff durchzuführen, und um beliebigen Programmcode auszuführen.