CVE-2026-59180: Apprise forwards configured auth headers across cross-origin HTTP redirects

Apprise’s HTTP-based notification plugins and its HTTP attachment / config loaders (apprise/attachment/http.py, apprise/config/http.py) follow HTTP 3xx redirects by default and re-send the user-configured auth headers and query parameters on the redirected request. If an operator-configured destination is later compromised (service takeover, malicious update), or an attacker holds a MITM position on an unprotected network path, that destination can return a 302 Location: to an arbitrary host and Apprise forwards the user’s secret (X-Gotify-Key, Authorization, bearer tokens in query, custom +Header= values) to that cross-origin host. The attacker does not need to control the original Apprise URL — only the response from a destination the operator already trusts.

This is the application-layer analogue of urllib3 GHSA-34jh-p97f-mpxf / CVE-2026-44431 ("Proxy-Authorization forwarded across cross-origin redirect").