REDHAT-BUG-2421349: High severity libsoup vulnerability

Published Dec 11, 2025
·
Updated

libsoup accepts duplicate Host: headers and implements a last-value-wins policy when soupmessageheadersgetone[common] is used to construct the request URI, while many proxies and routers use the first Host: header for routing. The provided PoC reliably demonstrates that a proxy honoring the first Host: can route to backend A but the libsoup server will interpret the request as for host B (last header), enabling virtual-host confusion and potential bypasses of host-based ACLs or cache poisoning.

Affected Software

1 affected component
libsoup

Event History

Dec 11, 2025
Data Sourced
via Red Hat·07:35 AM
DescriptionSeverityAffected Software
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Frequently Asked Questions

1

What is the severity of REDHAT-BUG-2421349?

The severity of REDHAT-BUG-2421349 is considered to be moderate due to the potential for improper request routing.

2

How do I fix REDHAT-BUG-2421349?

To fix REDHAT-BUG-2421349, ensure that your application properly validates and processes Host headers to prevent unexpected behavior.

3

What systems are affected by REDHAT-BUG-2421349?

REDHAT-BUG-2421349 affects any systems using libsoup that do not handle duplicate Host headers properly.

4

What are the risks associated with REDHAT-BUG-2421349?

The risks associated with REDHAT-BUG-2421349 include potential misrouting of requests leading to exposure of sensitive data.

5

Is there a workaround for REDHAT-BUG-2421349?

A possible workaround for REDHAT-BUG-2421349 is to filter or sanitize Host headers before processing requests.

Contact

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