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Apache CXF OAuth2 HTTP Response Splitting via WWW-Authenticate Realm Injection

Moderate severity GitHub Reviewed Published Jun 12, 2026 to the GitHub Advisory Database • Updated Aug 20, 2026

Package

maven org.apache.cxf:cxf-rt-rs-security-oauth2 (Maven)

Affected versions

>= 4.2.0, < 4.2.2
< 4.1.7

Patched versions

4.2.2
4.1.7

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, which fixes this issue.

References

Published by the National Vulnerability Database Jun 12, 2026
Published to the GitHub Advisory Database Jun 12, 2026
Reviewed Aug 20, 2026
Last updated Aug 20, 2026

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(49th percentile)

Weaknesses

Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting')

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. Learn more on MITRE.

CVE ID

CVE-2026-50630

GHSA ID

GHSA-xf62-wr5p-5p95

Source code

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