CVE-2025-8582: Google Chrome XSS Vulnerability

CVE-2025-8582 Overview

CVE-2025-8582 affects Google Chrome versions prior to 139.0.7258.66 on Windows, macOS, and Linux. The vulnerability stems from insufficient validation of untrusted input in the Chrome Core component. A remote attacker can spoof the contents of the Omnibox (URL bar) using a crafted HTML page. Chromium classifies the underlying security severity as Low, while NVD scores the issue at 4.3 under CVSS v3.1. The weakness maps to [CWE-20] Improper Input Validation. Successful exploitation requires user interaction, such as visiting an attacker-controlled page, and enables phishing scenarios where users see a trusted URL while viewing attacker-controlled content.

Critical Impact
Attackers can manipulate the displayed URL in the Chrome address bar to impersonate legitimate sites, undermining the primary visual trust signal users rely on to identify phishing pages.

Affected Products

Google Chrome prior to 139.0.7258.66 on Microsoft Windows
Google Chrome prior to 139.0.7258.66 on Apple macOS
Google Chrome prior to 139.0.7258.66 on Linux

Discovery Timeline

2025-08-07 - CVE-2025-8582 published to NVD
2025-08-07 - Google releases fixed Chrome build 139.0.7258.66 via the Stable channel
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-8582

Vulnerability Analysis

CVE-2025-8582 is an Omnibox spoofing flaw in Chrome's Core component. The Omnibox is the combined address and search bar that users depend on to verify the origin of loaded content. When Chrome fails to properly validate specific untrusted input embedded in an HTML page, the browser renders content from one origin while the Omnibox displays a different URL. This visual mismatch defeats the primary anti-phishing indicator in the browser user interface.

The issue is classified under [CWE-20] Improper Input Validation. The CVSS vector reflects a network-reachable weakness with low attack complexity, no privileges required, and user interaction needed to trigger exploitation. Impact is limited to integrity, which aligns with the spoofing outcome. There is no confidentiality or availability effect and no direct code execution. Chromium engineers rated the internal severity as Low, and no exploitation in the wild has been reported. The EPSS forecast places exploitation probability at a low tier.

Root Cause

The root cause is insufficient validation of untrusted input processed by Chrome Core when rendering pages and updating the address bar state. A crafted HTML page can drive the Omnibox into a state that no longer reflects the actual document origin, producing a spoofed URL display.

Attack Vector

Exploitation requires a victim to visit an attacker-controlled or compromised web page. No authentication is needed. The attacker crafts HTML that manipulates navigation and URL display logic so the Omnibox shows a URL of the attacker's choosing while attacker content is rendered. This enables convincing phishing pages that mimic banking, SaaS, or identity provider login flows. Detailed reproduction data is tracked in the Chromium Issue Tracker Entry.

Detection Methods for CVE-2025-8582

Indicators of Compromise

Chrome browser processes reporting versions below 139.0.7258.66 in endpoint inventory data.
User reports of URL bar contents that do not match the visible page content or expected destination.
Web proxy logs showing navigations to newly registered or low-reputation domains referenced by phishing campaigns.

Detection Strategies

Query endpoint telemetry for the installed Chrome version and flag hosts running builds earlier than 139.0.7258.66.
Correlate DNS and HTTP telemetry with credential-submission events to surface phishing landings that may leverage Omnibox spoofing.
Monitor security awareness reporting channels for user-submitted phishing samples that reference mismatched URLs.

Monitoring Recommendations

Track Chrome update compliance in software inventory dashboards and alert on hosts stalled on outdated versions.
Enrich proxy and email gateway logs with URL reputation and typosquatting scoring to identify likely phishing lures.
Review authentication logs from identity providers for unusual sign-in patterns following user visits to unknown domains.

How to Mitigate CVE-2025-8582

Immediate Actions Required

Update Chrome to 139.0.7258.66 or later on all Windows, macOS, and Linux endpoints.
Force-restart Chrome on managed endpoints to ensure the patched build is loaded into memory.
Verify enterprise update policies through chrome://policy and confirm the UpdateDefault and TargetVersionPrefix values allow the fixed release.

Patch Information

Google shipped the fix in the Chrome Stable channel build 139.0.7258.66. Deployment details and channel notes are available in the Google Chrome Desktop Update release announcement. Enterprises using Chrome Browser Cloud Management or MDM should push the updated MSI, PKG, or DEB packages to close the window of exposure.

Workarounds

Train users to verify page identity through TLS certificate details rather than relying solely on the URL bar until patching is complete.
Restrict browsing to known-good destinations via web filtering categories where feasible.
Enable Enhanced Safe Browsing in Chrome to increase warnings on newly observed phishing domains.

bash

# Verify installed Chrome version on Linux endpoints
google-chrome --version

# Windows: query the installed version via registry
reg query "HKLM\SOFTWARE\Google\Update\Clients\{8A69D345-D564-463C-AFF1-A69D9E530F96}" /v pv

# macOS: query installed version via defaults
defaults read /Applications/Google\ Chrome.app/Contents/Info CFBundleShortVersionString