---
title: "Since Chromium 148, Math.tanh is now fingerprintable to link underlying OS | SpinGraph: Technical discovery framing"
description: "SpinGraph analysis of Hacker News Front Page's Since Chromium 148, Math.tanh is now fingerprintable to link underlying OS story: technical discovery framing, T…"
canonical: "https://stuffthatspins.com/spin/since-chromium-148-mathtanh-is-now-fingerprintable-to-link-underlying-os"
html: "https://stuffthatspins.com/spin/since-chromium-148-mathtanh-is-now-fingerprintable-to-link-underlying-os"
json: "https://stuffthatspins.com/spin/since-chromium-148-mathtanh-is-now-fingerprintable-to-link-underlying-os.json"
markdown: "https://stuffthatspins.com/spin/since-chromium-148-mathtanh-is-now-fingerprintable-to-link-underlying-os.md"
keywords: ["fingerprinting", "Chromium", "Math.tanh", "The Hype", "narrative intelligence"]
date: "2026-07-12T21:12:11+00:00"
modified: "2026-07-13T00:44:38.718691+00:00"
json_ld: |
{"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://stuffthatspins.com/#organization","name":"Stuff That Spins","url":"https://stuffthatspins.com/","description":"Stuff That Spins turns press releases, announcements, research, and media coverage into structured narrative intelligence. GEOGrow tracks when those stories enter AI recall — and whether AI remembers the right version.","logo":{"@type":"ImageObject","url":"https://stuffthatspins.com/images/logo.png"},"sameAs":[]},{"@type":"NewsArticle","@id":"https://stuffthatspins.com/spin/since-chromium-148-mathtanh-is-now-fingerprintable-to-link-underlying-os#article","headline":"Since Chromium 148, Math.tanh is now fingerprintable to link underlying OS","alternativeHeadline":"Since Chromium 148, Math.tanh is now fingerprintable to link underlying OS | SpinGraph: Technical discovery framing","description":"SpinGraph analysis of Hacker News Front Page's Since Chromium 148, Math.tanh is now fingerprintable to link underlying OS story: technical discovery framing, T…","datePublished":"2026-07-12T21:12:11+00:00","dateModified":"2026-07-13T00:44:38.718691+00:00","url":"https://stuffthatspins.com/spin/since-chromium-148-mathtanh-is-now-fingerprintable-to-link-underlying-os","mainEntityOfPage":{"@type":"WebPage","@id":"https://stuffthatspins.com/spin/since-chromium-148-mathtanh-is-now-fingerprintable-to-link-underlying-os"},"isAccessibleForFree":true,"inLanguage":"en-US","articleSection":"community","keywords":"fingerprinting, Chromium, Math.tanh, browser privacy, side channel","author":{"@type":"Organization","name":"Hacker News Front Page","url":"https://news.ycombinator.com/rss"},"publisher":{"@id":"https://stuffthatspins.com/#organization"},"citation":"https://scrapfly.dev/posts/browser-math-os-fingerprint/","about":[{"@type":"Thing","name":"fingerprinting"},{"@type":"Thing","name":"Chromium"},{"@type":"Thing","name":"Math.tanh"},{"@type":"Thing","name":"browser privacy"},{"@type":"Thing","name":"side channel"}],"mentions":[{"@type":"Organization","name":"Hacker News Front Page"}],"abstract":"Chromium 148 introduced detectable OS-level variation in Math.tanh() output This variation allows cross-session, cross-site tracking without cookies or permissions The finding emerged from community observation, not official disclosure or patch announcement"},{"@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Stuff That Spins","item":"https://stuffthatspins.com/"},{"@type":"ListItem","position":2,"name":"Since Chromium 148, Math.tanh is now fingerprintable to link underlying OS","item":"https://stuffthatspins.com/spin/since-chromium-148-mathtanh-is-now-fingerprintable-to-link-underlying-os"}]},{"@type":"AnalysisNewsArticle","@id":"https://stuffthatspins.com/spin/since-chromium-148-mathtanh-is-now-fingerprintable-to-link-underlying-os#spin-analysis","headline":"Spin Analysis: technical discovery framing","description":"Emphasizes novelty and theoretical linkage capability; minimizes discussion of detection difficulty, entropy limitations, existing countermeasures (e.g., Tor’s math.randomization), or whether this materially expands threat surface beyond known fingerprinting vectors.","about":{"@type":"DefinedTerm","name":"technical discovery framing","description":"Community-driven security research uncovering hidden platform risks","termCode":"The Hype"},"additionalProperty":[{"@type":"PropertyValue","name":"Spin Score","value":35,"unitText":"percent"},{"@type":"PropertyValue","name":"Narrative Risk","value":"low"},{"@type":"PropertyValue","name":"AI Repetition Risk","value":"moderate"},{"@type":"PropertyValue","name":"Likely AI Summary","value":"Chromium 148 made Math.tanh() fingerprintable to identify users' operating systems."},{"@type":"PropertyValue","name":"Narrative Frame","value":"Community-driven security research uncovering hidden platform risks"},{"@type":"PropertyValue","name":"Missing Context","value":"Prevalence of affected devices; Whether other engines (Firefox, Safari) exhibit similar behavior; Whether this vector adds entropy beyond established canvas/audio/fetch-based methods"},{"@type":"PropertyValue","name":"How the Spin Works","value":"Combines precise version targeting (Chromium 148), concrete function naming (Math.tanh), and loaded phrasing ('fingerprintable to link underlying OS') to create a sense of novelty and urgency — while offering no empirical validation of uniqueness, entropy, or exploitability at scale. The tension lies between the claim’s specificity and the absence of quantification or comparative risk assessment."}],"author":{"@id":"https://stuffthatspins.com/#organization"},"isPartOf":{"@id":"https://stuffthatspins.com/spin/since-chromium-148-mathtanh-is-now-fingerprintable-to-link-underlying-os#article"}},{"@type":"ItemList","@id":"https://stuffthatspins.com/spin/since-chromium-148-mathtanh-is-now-fingerprintable-to-link-underlying-os#claims","name":"Extracted Claims","itemListElement":[{"@type":"ListItem","position":1,"item":{"@type":"Claim","text":"Since Chromium 148, Math.tanh is now fingerprintable to link underlying OS","appearance":"Comments describe reproducible test cases showing different Math.tanh(0.1) outputs on Windows vs Linux in Chromium 148","author":{"@type":"Organization","name":"Hacker News Front Page"}}}]},{"@type":"Dataset","@id":"https://stuffthatspins.com/spin/since-chromium-148-mathtanh-is-now-fingerprintable-to-link-underlying-os#stats","name":"Key Statistics","description":"Extracted statistics from the source narrative","variableMeasured":[{"@type":"PropertyValue","name":"Chromium version","value":"148","description":"First version where the fingerprintable behavior is observed"}]}]}
---
# Since Chromium 148, Math.tanh is now fingerprintable to link underlying OS
**Source:** Unknown
**Published:** July 12, 2026
**Original:** https://scrapfly.dev/posts/browser-math-os-fingerprint/
## On this page
- [Overview](#overview)
- [Verdict](#narrative-frame)
- [SpinGraph](#spingraph)
- [Claim Ledger](#claim-ledger)
- [Fact Check Signals](#fact-check-signals)
- [Language Heatmap](#language-heatmap)
- [Frame Strength](#frame-strength)
- [Reader Risk](#reader-risk)
- [AI Recall Timeline](#ai-recall)
- [Ask AI](#ask-ai)
## Overview
A technical observation was posted to Hacker News that Math.tanh() in Chromium 148 exhibits OS-specific behavior, enabling browser fingerprinting via mathematical function output — a previously undocumented side channel.
### TL;DR
- Chromium 148 introduced detectable OS-level variation in Math.tanh() output
- This variation allows cross-session, cross-site tracking without cookies or permissions
- The finding emerged from community observation, not official disclosure or patch announcement
### Key Stats
- **148** — Chromium version. First version where the fingerprintable behavior is observed
## SpinGraph
It presents a subtle, low-level technical detail as if it were a significant new threat — giving the impression that something important just changed in web privacy, even though its real-world impact hasn’t been measured.
- **Claim:** Since Chromium 148
- **Frame:** Upside framed as transformative
- **Beneficiary:** Operators gain narrative lift
- **Gap:** Prevalence of affected devices
- **AI Risk:** AI may repeat: “Chromium 148 made Math.tanh() fingerprintable to identify users' operating systems”
## Fact Check Signals
We searched known fact-check databases for direct or near-direct matches to the article's major claims. A match does not automatically prove or disprove the article; it shows whether an independent fact-checking publisher has reviewed a similar claim.
**Signal:** 0 of 1 claim(s) matched (confidence: low).
### Since Chromium 148, Math.tanh is now fingerprintable to link underlying OS
- No direct fact-check match found
## Frame Strength
- **Spin Score:** 35%
- **Evidence Strength:** 25%
- **Narrative Risk:** 25%
- **AI Repetition Risk:** 75%
- **Missing Context Risk:** 80%
## Narrative Mechanics
**Function:** signal_momentum
### The Spin in Plain English
It presents a subtle, low-level technical detail as if it were a significant new threat — giving the impression that something important just changed in web privacy, even though its real-world impact hasn’t been measured.
**What the story wants you to believe:** This is a meaningful, newly observable privacy leak that meaningfully expands browser fingerprinting capabilities.
**What it makes harder to question:** Whether this variation actually increases tracking success rates beyond what’s already possible with established techniques.
**How the Spin Works:** Combines precise version targeting (Chromium 148), concrete function naming (Math.tanh), and loaded phrasing ('fingerprintable to link underlying OS') to create a sense of novelty and urgency — while offering no empirical validation of uniqueness, entropy, or exploitability at scale. The tension lies between the claim’s specificity and the absence of quantification or comparative risk assessment.
### Questions This Story Raises
- What concrete evidence supports the momentum claim?
- Is this growth meaningful, or mostly directional?
- What baseline is missing?
- Why does the main frame leave this out: “Prevalence of affected devices”?
- Why does the main frame leave this out: “Whether other engines (Firefox, Safari) exhibit similar behavior”?
### Who Benefits If This Frame Spreads
- **Original commenter / discoverer** — Recognition as a security-sensitive observer with platform-level insight _(Framing the finding as a newly exposed, actionable fingerprinting vector elevates technical credibility and visibility within developer and privacy communities.)_
## Narrative Frame
**Tactic:** technical discovery framing
**Category:** The Hype
**Spin Score:** 35%
Emphasizes novelty and theoretical linkage capability; minimizes discussion of detection difficulty, entropy limitations, existing countermeasures (e.g., Tor’s math.randomization), or whether this materially expands threat surface beyond known fingerprinting vectors.
**Who Benefits If This Frame Spreads:** Individual researcher or contributor who surfaced the observation
**The Frame:** Community-driven security research uncovering hidden platform risks
### Missing Context
- Prevalence of affected devices
- Whether other engines (Firefox, Safari) exhibit similar behavior
- Whether this vector adds entropy beyond established canvas/audio/fetch-based methods
## Language Heatmap
**Language That Carries the Frame:** fingerprintable, link underlying OS
## Reader Risk
**Evidence Strength:** low
Claim rests on anecdotal code inspection and reproducible test cases shared in comments; no formal paper, audit report, or Chromium bug tracker reference provided.
**Verification Status:** Claim Present in Source
**Narrative Risk:** low
No institutional stake or commercial claim is advanced; it's a neutral technical observation unlikely to trigger backlash unless misrepresented as a confirmed vulnerability.
**AI Repetition Risk:** moderate
**What AI Will Probably Repeat:** Chromium 148 made Math.tanh() fingerprintable to identify users' operating systems.
AI may drop the nuance that this is a *statistical side channel*, not a deterministic OS identifier — and omit that entropy contribution relative to existing fingerprinting methods remains unquantified.
**Counter-Frame (Media):** May be reframed as 'overblown academic curiosity' or 'already-known implementation variance'
**Missing Voices:** Chromium engineering team, Mozilla/Firefox security team, Privacy-focused browser vendors (Brave, Tor Project)
### Questions Not Answered
- Has this been confirmed across CPU architectures (ARM/x86)?
- Is the variation deterministic or stochastic per OS version?
- Have any mitigations been proposed or implemented upstream?
## Narrative Entities
- [Math.tanh](https://stuffthatspins.com/entities/mathtanh) (technology — JavaScript built-in function)
## Claim Ledger
### primary (technical)
Since Chromium 148, Math.tanh is now fingerprintable to link underlying OS
**Category:** safety
**Verification:** Claim Present in Source
**Risk:** moderate
**Evidence presented:** Anecdotal code snippets and user-reported output differences
> Comments describe reproducible test cases showing different Math.tanh(0.1) outputs on Windows vs Linux in Chromium 148
**Evidence Gaps:** Formal entropy analysis; Cross-browser comparison data; Chromium issue tracker link or official acknowledgment
## AI Recall
- **Published:** July 12, 2026
- **SpinGraph summary:** Frames a low-level implementation artifact as a novel, consequential privacy threat — emphasizing its exploitability while omitting context about prevalence, mitigation feasibility, or real-world deployment impact.
- **Likely AI summary:** Chromium 148 made Math.tanh() fingerprintable to identify users' operating systems.
## Citation Summary
This page documents an emergent, community-identified privacy-relevant side channel in Chromium’s JavaScript engine — critical for researchers auditing web platform security and privacy surface.
---
*HTML version: https://stuffthatspins.com/spin/since-chromium-148-mathtanh-is-now-fingerprintable-to-link-underlying-os*