CVE-2025-6442

Ruby WEBrick read_header HTTP Request Smuggling Vulnerability. This vulnerability allows remote attackers to smuggle arbitrary HTTP requests on affected installations of Ruby WEBrick. This issue is exploitable when the product is deployed behind an HTTP proxy that fulfills specific conditions.

The specific flaw exists within the read_headers method. The issue results from the inconsistent parsing of terminators of HTTP headers. An attacker can leverage this vulnerability to smuggle arbitrary HTTP requests. Was ZDI-CAN-21876.

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):

Webrick is an open source HTTP server toolkit for The Ruby Programming Language. Webrick has an environmental problem vulnerability, which originates from the inconsistent parsing of HTTP header terminators by the read_headers method, which may lead to an HTTP request entrainment attack.(CVE-2025-6442)

Ruby WEBrick read_header HTTP Request Smuggling Vulnerability. This vulnerability allows remote attackers to smuggle arbitrary HTTP requests on affected installations of Ruby WEBrick. This issue is exploitable when the product is deployed behind an HTTP proxy that fulfills specific conditions. The specific flaw exists within the read_headers method. The issue results from the inconsistent parsing of terminators of HTTP headers. An attacker can leverage this vulnerability to smuggle arbitrary HTTP requests. Was ZDI-CAN-21876.

Ruby WEBrick read_header HTTP Request Smuggling Vulnerability. This vulnerability allows remote attackers to smuggle arbitrary HTTP requests on affected installations of Ruby WEBrick. This issue is exploitable when the product is deployed behind an HTTP proxy that fulfills specific conditions.

The specific flaw exists within the read_headers method. The issue results from the inconsistent parsing of terminators of HTTP headers. An attacker can leverage this vulnerability to smuggle arbitrary HTTP requests. Was ZDI-CAN-21876.

Ruby WEBrick read_header HTTP Request Smuggling Vulnerability. This vulnerability allows remote attackers to smuggle arbitrary HTTP requests on affected installations of Ruby WEBrick. This issue is exploitable when the product is deployed behind an HTTP proxy that fulfills specific conditions.

The specific flaw exists within the read_headers method. The issue results from the inconsistent parsing of terminators of HTTP headers. An attacker can leverage this vulnerability to smuggle arbitrary HTTP requests. Was ZDI-CAN-21876.

Ruby WEBrick read_header HTTP Request Smuggling Vulnerability. This vulnerability allows remote attackers to smuggle arbitrary HTTP requests on affected installations of Ruby WEBrick. This issue is exploitable when the product is deployed behind an HTTP proxy that fulfills specific conditions.

The specific flaw exists within the read_headers method. The issue results from the inconsistent parsing of terminators of HTTP headers. An attacker can leverage this vulnerability to smuggle arbitrary HTTP requests. Was ZDI-CAN-21876.

Ruby WEBrick read_header HTTP Request Smuggling Vulnerability. This vulnerability allows remote attackers to smuggle arbitrary HTTP requests on affected installations of Ruby WEBrick. This issue is exploitable when the product is deployed behind an HTTP proxy that fulfills specific conditions.

The specific flaw exists within the read_headers method. The issue results from the inconsistent parsing of terminators of HTTP headers. An attacker can leverage this vulnerability to smuggle arbitrary HTTP requests. Was ZDI-CAN-21876.

This update for ruby2.5 fixes the following issues:

• CVE-2025-6442: Fixed read_header HTTP Request Smuggling Vulnerability in WEBrick (bsc#1245254)
• CVE-2025-27221: Fixed userinfo leakage in URI#join, URI#merge and URI#+ (bsc#1237805)

This update for ruby2.5 fixes the following issues:

• CVE-2025-6442: Fixed read_header HTTP Request Smuggling Vulnerability in WEBrick (bsc#1245254)
• CVE-2025-27221: Fixed userinfo leakage in URI#join, URI#merge and URI#+ (bsc#1237805)

This update for ruby2.5 fixes the following issues:

• CVE-2024-35221: Fixed remote DoS via YAML manifest (bsc#1225905)
• CVE-2024-47220: Fixed HTTP request smuggling in WEBrick (bsc#1230930)
• CVE-2024-49761: Fixed ReDOS vulnerability by updating REXML to 3.3.9 (bsc#1232440)
• CVE-2025-24294: Fixed denial of service (DoS) caused by an insufficient check on the length of a decompressed domain name within a DNS packet in resolv gem (bsc#1246430)
• CVE-2025-27219: Fixed denial of service in CGI::Cookie.parse (bsc#1237804)
• CVE-2025-27220: Fixed ReDoS in CGI::Util#escapeElement (bsc#1237806)
• CVE-2025-27221: Fixed userinfo leakage in URI#join, URI#merge and URI#+ (bsc#1237805)
• CVE-2025-6442: Fixed ruby WEBrick read_header HTTP request smuggling vulnerability (bsc#1245254)

It was discovered that WEBrick incorrectly parsed HTTP headers. In configurations where WEBrick is placed behind an HTTP proxy, a remote attacker could possibly use this issue to perform an HTTP Request Smuggling attack.

It was discovered that the REXML module bunded into Ruby incorrectly handled parsing XML documents with repeated instances of certain characters. An attacker could possibly use this issue to cause REXML to consume excessive resources, leading to a denial of service. Ubuntu 18.04 LTS and Ubuntu 20.04 LTS were previously addressed in USN-7256-1 and USN-7734-1. This update addresses the issue in Ubuntu 16.04 LTS. (CVE-2024-35176)

It was discovered that the REXML module bunded into Ruby incorrectly handled parsing XML documents with repeated instances of certain characters. An attacker could possibly use this issue to cause REXML to consume excessive resources, leading to a denial of service. Ubuntu 20.04 LTS was previously addressed in USN-7256-1. This update addresses the issue in Ubuntu 16.04 LTS and Ubuntu 18.04 LTS. (CVE-2024-39908, CVE-2024-41123)

It was discovered that the REXML module bunded into Ruby incorrectly handled parsing XML documents with many entity expansions. An attacker could possibly use this issue to cause REXML to consume excessive resources, leading to a denial of service. Ubuntu 20.04 LTS was previously addressed in USN-7091-2. This update addresses the issue in Ubuntu 16.04 LTS and Ubuntu 18.04 LTS. (CVE-2024-41946)

It was discovered that the WEBrick module bundled into Ruby incorrectly handled having both a Content-Length header and a Transfer-Encoding header. A remote attacker could possibly use this issue to perform a HTTP request smuggling attack. (CVE-2024-47220)

It was discovered that the WEBrick module bundled into Ruby incorrectly parsed HTTP headers. In configurations where the WEBrick module is placed behind an HTTP proxy, a remote attacker could possibly use this issue to perform an HTTP Request Smuggling attack. (CVE-2025-6442)