Apache CXF up to 4.1.6/4.2.1 OAuth2 response splitting

Summaryinfo

A vulnerability, which was classified as critical, has been found in Apache CXF up to 4.1.6/4.2.1. Affected by this vulnerability is an unknown functionality of the component OAuth2. The manipulation leads to response splitting. This vulnerability is traded as CVE-2026-50630. It is possible to initiate the attack remotely. There is no exploit available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as critical, has been found in Apache CXF up to 4.1.6/4.2.1. This issue affects an unknown functionality of the component OAuth2. The manipulation with an unknown input leads to a response splitting vulnerability. Using CWE to declare the problem leads to CWE-113. The product receives data from an HTTP agent/component (e.g., web server, proxy, browser, etc.), but it does not neutralize or incorrectly neutralizes CR and LF characters before the data is included in outgoing HTTP headers. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

A CRLF injection vulnerability exists in the OAuth2 AuthorizationUtils class. When constructing the WWW-Authenticate response header, the 'realm' parameter is concatenated without sanitizing Carriage Return (CR) and Line Feed (LF) characters. If an attacker can control the realm value, they can inject arbitrary HTTP headers or split the HTTP response entirely. Users are recommended to upgrade to versions 4.2.2 or 4.1.7 or 3.6.12, which fixes this issue.

The advisory is shared at lists.apache.org. The identification of this vulnerability is CVE-2026-50630. The exploitation is known to be easy. The attack may be initiated remotely. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 08/07/2026).

Upgrading to version 4.1.7 or 4.2.2 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at CERT Bund (WID-SEC-2026-1895). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Affected

• Apache CXF

Productinfo

Type

• Application Server Software

Vendor

• Apache

Name

• CXF

Version

• 4.1.0
• 4.1.1
• 4.1.2
• 4.1.3
• 4.1.4
• 4.1.5
• 4.1.6
• 4.2.0
• 4.2.1

License

• open-source

Website

• Vendor: https://www.apache.org/

CPE 2.3info

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CPE 2.2info

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If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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