Actively exploited vulnerability

Google Chromium Intents: improper access control flaw under attack

CVE-2021-38000 · Google Chromium Intents Improper Input Validation Vulnerability

Concerns everyone who uses it6.1 medium

What is affected

Google Chromium Intents is found on ordinary personal computers and phones, so this is not only a problem for companies. If you use it and have not updated since the fix was released, you are exposed.

Google Chromium Intents contains an improper input validation vulnerability that allows a remote attacker to arbitrarily browser to a malicious URL via a crafted HTML page. This vulnerability could affect multiple web browsers that utilize Chromium, including, but not limited to, Google Chrome, Microsoft Edge, and Opera.

CISA's description

What an attacker can do

This is a improper access control flaw. It lets an attacker perform actions or reach data that should be restricted to authorised users.

How it is reached
Over the internet or network
Access the attacker needs
No account needed
Does the victim have to do something?
Yes, the victim must open or click something

What to do

  1. Update Google Chromium Intents now. Open the update or "About" screen, install whatever is offered and restart the app or device, because the fix is not active until you do.
  2. Turn on automatic updates so the next fix arrives without you having to look for it.
  3. If your device is too old to receive this update, stop using the affected app for anything sensitive and plan a replacement.

Apply updates per vendor instructions.

Action required by CISA for US federal agencies

How urgent is it

CISA added this vulnerability to its Known Exploited Vulnerabilities catalogue on November 3, 2021, which means there is reliable evidence of attacks in the wild. US federal agencies must fix it by November 17, 2021, a deadline that has already passed. That deadline does not bind anyone else, but it shows how seriously the agency rates it.

The EPSS model estimates a 4.9% probability that this flaw will be exploited somewhere in the next 30 days. That is higher than 92% of all scored vulnerabilities.

Its CVSS severity score is 6.1 out of 10 (medium), as recorded in the US National Vulnerability Database.

Technical description

Insufficient validation of untrusted input in Intents in Google Chrome on Android prior to 95.0.4638.69 allowed a remote attacker to arbitrarily browser to a malicious URL via a crafted HTML page.

NIST National Vulnerability Database
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