Impact When following cross-origin redirects for requests made using urllib3’s high-level APIs, such as "urllib3.request()", "PoolManager.request()", and "ProxyManager.request()", sensitive headers — "Authorization", "Cookie", and "Proxy-Authorization" (defined in "Retry.DEFAULT_REMOVE_HEADERS_ON_REDIRECT") — are stripped by default, as expected. However, cross-origin redirects followed from the low-level API via "ProxyManager.connection_from_url().urlopen(..., assert_same_host=False)" still forward these sensitive headers. Affected usage Applications and libraries using urllib3 versions earlier than 2.7.0 may be affected if they allow cross-origin redirects while making requests through "HTTPConnection.urlopen()" instances created via "ProxyManager.connection_from_url()". Remediation Upgrade to urllib3 version 2.7.0 or later, in which sensitive headers are stripped from redirects followed by "HTTPConnection". If upgrading is not immediately possible, avoid using this low-level redirect flow for cross-origin redirects. If appropriate for your use case, switch to "ProxyManager.request()".