---
id: "CVE-2026-96203"
kind: "vulnerability"
aliases: ["CVE-2026-96203"]
title: "Microsoft Edge: use-after-free lets a network attacker gain higher privileges"
severity: "high"
cvss: 8.8
epss: null
exploited: false
status: "open"
category: "other"
products: [{"name": "Microsoft Edge (Chromium-based)", "fixed": ["155.0.4283.45"], "affected": "< 155.0.4283.45", "ecosystem": "vendor"}]
ecosystems: []
tags: ["browser", "chromium", "microsoft-edge", "other", "use-after-free", "windows"]
not_affected_if: ["patched-edge-155.0.4283.45"]
published_at: "2026-10-29T16:20:09+00:00"
first_seen_at: "2026-10-29T16:26:04+00:00"
updated_at: "2026-10-29T16:33:51+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-96203", "first_seen_at": "2026-10-29T16:26:04+00:00"}, {"source": "analyst", "url": null, "first_seen_at": "2026-10-29T16:33:51+00:00"}]
---

# Microsoft Edge: use-after-free lets a network attacker gain higher privileges

A use-after-free bug in Microsoft Edge (Chromium-based) lets an unauthorized attacker elevate privileges over a network. The sources give no further detail on the trigger or the exact privilege gained.

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

## Affected

- vendor:Microsoft Edge (Chromium-based) affected < 155.0.4283.45 fixed 155.0.4283.45

## How to check

Edge menu > Help and feedback > About Microsoft Edge; vulnerable if the version is below 155.0.4283.45. Check by command: msedge --version or (Get-Item 'C:\Program Files (x86)\Microsoft\Edge\Application\msedge.exe').VersionInfo.ProductVersion

## Fix

Update Microsoft Edge (Chromium-based) to 155.0.4283.45 or later (per MSRC mirror; confirm on the MSRC page). Current Stable is 156.0.4314.42.

## Timeline

- 2026-10-29T16:26:04+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-96203
- 2026-10-29T16:33:51+00:00 analyst — MSRC page is JS-rendered and unreadable to me; fixed build 155.0.4283.45 comes from an MSRC mirror (EchelonGraph) and OffSeq, not confirmed on a vendor page, so nothing marked verified. Edge release notes list 155.0.4283.45 as Stable on Oct 8 (later stable 156.0.4314.42 Oct 22) but do not list this CVE. CVSS 8.8 needs user interaction (UI:R). No exploitation or PoC found; no X search done.

## Documents

- [advisory] MSRC Security Update Guide: CVE-2026-96203 (page is JS-rendered, text not readable) https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-96203
- [fix] Microsoft Edge security release notes https://learn.microsoft.com/en-us/deployedge/microsoft-edge-relnotes-security
- [mentions] EchelonGraph mirror of MSRC entry (fixed build 155.0.4283.45) https://echelongraph.io/pulse/vendor-advisories/microsoft/CVE-2026-96203

## From the sources

Use after free in Microsoft Edge (Chromium-based) allows an unauthorized attacker to elevate privileges over a network.

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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_