CVE-2026-50630: Apache CXF: OAuth2: HTTP Response Splitting via WWW-Authenticate Realm Injection

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-06-12 · updated 2026-10-26
Weakness: CWE-113

Description

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.

Affected products

Apache Software Foundation Apache CXF: before 4.1.7; from 4.2.0 before 4.2.2 — fixed in 4.1.7, 4.2.2

How to fix

Upgrade to a fixed version: Apache Software Foundation Apache CXF 4.1.7, 4.2.2. Check the vendor advisory for mitigations.

References

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