no notifications-permission headless bug
The two APIs agree; specifically, not query state 'prompt' alongside Notification.permission 'denied'.
What a detector infers
Two independent APIs describe the same underlying notification permission: navigator.permissions.query({name:'notifications'}) returns a PermissionStatus state, and Notification.permission returns a string. This check awaits the query and flags exactly one combination — state 'prompt' while Notification.permission is 'denied'.
In a coherent browser these cannot disagree, because they are two views of one stored setting; the pair diverges in certain headless configurations where the permission backend and the Notification interface are wired to different defaults. A detector reading both and comparing them needs no heuristic — the contradiction is decisive on its own, which is why the combination became a well-known probe.
Any exception during the query is swallowed and the check passes, so an environment lacking either API is not penalised.
How to resolve it
This is a property of the browser build and its headless mode rather than something to patch from page scripts — a build whose permission backend is coherent reports matching states. If you are overriding either API, override both from the same source of truth so they cannot diverge.
Read in the wild by
PerimeterX / HUMAN
Implements exactly this pair — it calls navigator.permissions.query({name:'notifications'}) only when Notification.permission already reads "denied", and when that query resolves to "prompt" it sets a flag whose own constant decodes to the string "permission_denied", which is written into the EV2 payload.
[internal reference] — plain literals, no decoding needed: `"denied"===Notification.permission&&eO[eK(217)].query({name:"notifications"}).then((function(e){"prompt"===e.state&&(lW=mo)}))`. Same pair in [internal reference] qF(): `if(!hU.permissions)return void(pi=pB);"denied"===Notification[t(189)]&&hU.permissions.query({name:"notifications"}).then((function(n){n.state===t(190)&&(pi=pA)}))`, where qF's function-local base91 dict decodes t(189)='permission' and t(190)='prompt'. The flag it sets is `pA=jb("cGVybWlzc2lvbl9kZW5pZWQ=")` = "permission_denied" (vs `pB`="no_permissions" when navigator.permissions is absent), and pi is written into the EV2 payload object via `t[0]["eytOYT5NSVM="]=pi` — sibling keys in that same object are tagged "src":"EV2" in [internal reference]. Pair present in three independent deployments ([site] ); `_pxAppId = "[site]"`.
CreepJS
CreepJS, an open-source fingerprinting research demo rather than a production detector, awaits navigator.permissions.query({ name: 'notifications' }) and compares its state against Notification.permission, treating the exact 'prompt'/'denied' pair as a property it names hasPermissionsBug — gated to Blink engines and filed under its 'likeHeadless' heuristics, which it keeps separate from its definitive 'headless' bucket.
src/headless/index.ts (abrahamjuliot/creepjs, master): `likeHeadless: {` … `hasPermissionsBug: (` `IS_BLINK &&` `'permissions' in navigator &&` `await (async () => {` `const res = await navigator.permissions.query({ name: 'notifications' })` `return (res.state == 'prompt' && 'Notification' in window && Notification.permission === 'denied')` `})()` `)` — distinct from the sibling single-read property `notificationIsDenied: (IS_BLINK && 'Notification' in window && (Notification.permission == 'denied'))`, and from the separate definitive `headless: {` bucket (webDriverIsOn, hasHeadlessUA, hasHeadlessWorkerUA).
Every attribution traces to a published artifact. See the sources and their limits.
Nearby checks in Automation surface
- no stylesheet is injecting custom properties into every page
injected-root-custom-propertiesA deployed commercial agent reads six CSS custom properties from the document's root element and reports true when four or more of them… - window.chrome present for a Chrome UA
chrome-objectThis is a cross-check, not a probe of window.chrome's contents: it first decides whether the browser claims to be Chrome (a Chrome/ token in… - window.chrome.* helpers are native (not JS stubs)
chrome-native-stubsWhere the previous check asks whether window.chrome exists, this one asks whether its members are genuine. - window.external is shaped the way the engine generates it
window-external-shapeA deployed commercial agent lists the absence of this object among its own named failure messages, which means it treats window.external… - permissions.query is native (arity throw + stack shape)
permissions-query-stackThis probe calls navigator.permissions.query() with exactly zero arguments and inspects the error the native arity check produces. - timer handles are a real per-realm counter
timer-id-sequencingThe number setTimeout hands back is not a token, it is an index into the realm's own timer table — so it carries structure that a fabricated… - the media-session counter runs forward and does not restart
eme-session-counter-monotonicA deployed commercial agent opens a ClearKey media session purely to read its identifier as a number — and then, if that number comes back… - the global object carries every platform global its claimed Chromium major carries
window-globals-vs-baselineThe list of names on the global object is not written by the page — it is installed by the engine when it sets up a realm, from a table…
Clearcote is a browser built for fingerprint coherence
It is a Chromium fork, maintained by the same people who wrote this reference. It ships as a compiled browser rather than as a stealth script injected into someone else's — which is a description of how it is built, and is not an argument about how it behaves on this check.
This audit takes no position on how Clearcote scores on Automation surface checks, on this one, or anywhere else. It has no baseline corpus of other people's fingerprints to rank you against and no vendor scoreboard — nearly every check is self-referential, asking one browser the same question through two independent APIs and reporting whether both answers can be true at once. It runs identically on any browser, including ours. Run it on yours and read the result yourself.
See the other checks in Automation surface — the family permissions-notification-bug belongs to.