---
id: "CVE-2026-121170"
kind: "vulnerability"
aliases: ["CVE-2026-121170"]
title: "Chrome: WebCodecs flaw lets a crafted web page bypass origin policy"
severity: "medium"
cvss: null
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["browsers", "chrome", "desktop", "package"]
not_affected_if: ["chrome-157-or-later"]
published_at: "2026-11-03T21:17:25+00:00"
first_seen_at: "2026-11-03T21:19:24+00:00"
updated_at: "2026-11-03T21:23:19+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-121170", "first_seen_at": "2026-11-03T21:19:24+00:00"}]
---

# Chrome: WebCodecs flaw lets a crafted web page bypass origin policy

Improper resource control in the WebCodecs API in Google Chrome before 157.0.8103.38 lets a remote attacker bypass the web origin policy using a crafted HTML page. Chromium rates it Medium severity.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the installed Chrome version at chrome://settings/help or with `google-chrome --version` on Linux.
- Compare it against the fixed version `157.0.8103.38`.

## Fix

- Google Chrome: move to `157.0.8103.38` or later.

## Timeline

- 2026-11-03T21:19:24+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-121170

## From the sources

Improper resource control in WebCodecs in Google Chrome prior to 157.0.8103.38 allowed a remote attacker to bypass web origin policy via a crafted HTML page. (Chromium security severity: Medium)

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_