Can malicious websites or network providers exploit browser fingerprinting to track users despite Private Relay?

1. Private Relay narrows one attack surface — but does not eliminate fingerprinting

Apple’s iCloud Private Relay masks the user’s real IP from the destination site and Apple by splitting requests over two relays, and it requires iCloud+ and Safari for that protection ^{[1] [2]}. Multiple explainers note this reduces IP-based linkage, but explicitly say Private Relay “won’t be much of a deterrent against fingerprinting” because fingerprinting draws on many device-level signals that Private Relay does not change ^{[3] [2]}.

2. What trackers can still read: the long list beyond IP addresses

Browser fingerprinting combines dozens of signals — screen size, installed fonts, hardware concurrency, canvas and WebGL/WebGPU behavior, time zone, and other browser-exposed APIs — into a persistent identifier. Guides and threat analysts say these signals remain available to websites and advertisers even when IP is hidden by Private Relay, so trackers can still create a stable profile ^{[5] [2]}.

3. Attackers who benefit: malicious sites vs. network providers

Available sources draw a distinction: Private Relay hides your IP from the site and from Apple (first- and second-party visibility), but does not change what the website can query through JavaScript. That means a malicious website can still harvest fingerprint signals and attempt to link visits, whereas network providers lose one easy stable identifier (your IP) but the sources do not say network providers gain new fingerprinting capabilities because of Private Relay — they are simply deprived of the raw IP ^{[1] [2] [3]}. Available sources do not mention a technique by which network providers can directly exploit Private Relay to increase fingerprinting power beyond what they could do before.

4. Real-world limits: uniqueness, cross-site linking and Apple’s design goals

Some modern defenses (and browser vendors’ strategies) try to reduce cross-site linking by making fingerprints site-unique or session-scoped; one write-up argues mitigations can make a fingerprint unique per website and reset each session, which defeats cross-site and cross-session linkage when properly implemented ^[1]. But that is not universal: browser behavior varies, and large commercial trackers — especially those using advertising platforms — continue to invest in probabilistic linking and cross-browser signals, a capability underscored by reporting on ad-industry changes in 2025 ^{[2] [6]}.

5. Stronger options: Tor and anti‑fingerprinting browsers

Security guides and anti-fingerprinting advocates point to the Tor Browser as the practical gold standard: it standardizes many signals so every user appears similar, blocks canvas reads, spoofs hardware concurrency, normalizes fonts and recently hardened features like WebGPU and letterboxing ^[4]. Several privacy guides and vendors advise switching to privacy-focused browsers or using anti-fingerprinting extensions — and warn that ordinary private/incognito modes do not stop fingerprinting ^{[5] [7]}.

6. Business and policy context: why trackers keep pushing fingerprinting

The advertising and measurement ecosystem has incentives to preserve cross-site identification as cookie-based techniques wane. Reporting shows large players and ad platforms have shifted or relaxed previous restrictions on fingerprinting, and some vendors now permit fingerprinting techniques within their products — increasing the business case for trackers to pair fingerprinting with whatever network-layer protections users adopt ^{[6] [2]}.

7. Practical advice and honest limits

If your goal is to stop IP-based linkage, enabling Private Relay in Safari reduces that specific risk ^{[1] [2]}. If your goal is to prevent fingerprint-based tracking entirely, available sources recommend using Tor Browser or browsers with dedicated anti‑fingerprinting features, because Private Relay alone does not block the broad set of signals used to fingerprint you ^{[4] [5] [3]}. Available sources do not provide evidence that Private Relay combined with mainstream browsers achieves the same anti‑fingerprinting guarantees as Tor ^{[4] [2]}.

Limitations: the reporting cited covers Apple Private Relay, browser defenses and the ad industry up to 2025; it does not claim exhaustive technical testing of every fingerprint vector on every browser or network. Where sources are silent about specific exploits or new relay behaviors, those details are “not found in current reporting” ^{[1] [2] [3]}.