CVE-2026-1539

A flaw was found in the libsoup HTTP library that can cause proxy authentication credentials to be sent to unintended destinations. When handling HTTP redirects, libsoup removes the Authorization header but does not remove the Proxy-Authorization header if the request is redirected to a different host. As a result, sensitive proxy credentials may be leaked to third-party servers. Applications using libsoup for HTTP communication may unintentionally expose proxy authentication data.

The Red Hat Product Security team has assessed the severity of this vulnerability as Medium. Exploitation requires network access but does not require authentication, user interaction, or special privileges. Successful exploitation may result in the disclosure of proxy authentication credentials to unintended third parties. While the issue does not directly allow code execution or service disruption, leakage of authentication material represents a meaningful confidentiality risk. The root cause is improper handling of sensitive headers during HTTP redirect processing.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.