CVE-2026-16416: Google Chrome Privilege Escalation Flaw

CVE-2026-16416 Overview

CVE-2026-16416 is an integer overflow vulnerability in the Chromecast component of Google Chrome prior to version 150.0.7871.182. A local attacker can trigger the overflow by sending malicious network traffic to a vulnerable Chrome instance. Successful exploitation may allow a sandbox escape, breaking the isolation boundary that constrains renderer and component processes. Google's Chromium project rated the security severity as High. The issue is tracked under CWE-190, Integer Overflow or Wraparound.

Critical Impact
An attacker on the local network can craft Chromecast traffic that triggers an integer overflow and potentially escapes the Chrome sandbox, exposing the host process context.

Affected Products

Google Chrome Desktop versions prior to 150.0.7871.182
Chromecast component within affected Chrome builds
Chromium-based browsers that ship the vulnerable Chromecast code path

Discovery Timeline

2026-07-21 - CVE-2026-16416 published to NVD
2026-07-21 - Last updated in NVD database
Referenced in Chrome Stable Channel Update and Chromium Issue #520172356

Technical Details for CVE-2026-16416

Vulnerability Analysis

The flaw resides in the Chromecast media receiver and discovery logic inside Chrome. Chromecast handles network payloads for device discovery, session negotiation, and media streaming. An integer overflow occurs when size or length fields in attacker-controlled network traffic are used in arithmetic without adequate bounds checks. The overflow produces a smaller-than-expected buffer allocation or index, which downstream code treats as valid.

Once the wrap-around occurs, subsequent memory operations write or read outside the intended allocation. This corruption is reachable from a process that runs Chromecast handling logic, providing a primitive that can be chained into a sandbox escape. Sandbox escape means the attacker's code executes outside the restricted renderer or utility sandbox and inside a higher-privilege Chrome broker context.

Root Cause

The root cause is unchecked arithmetic on length or count values derived from network input, consistent with CWE-190. When integer arithmetic wraps past INT_MAX or SIZE_MAX, allocators return undersized buffers while consumers assume the requested size. The mismatch produces an out-of-bounds memory access exploitable for control-flow corruption.

Attack Vector

Exploitation requires the attacker to reach the Chromecast network interface, typically on the same local network as the victim. The attacker sends crafted Chromecast discovery or media session packets to the browser. No user interaction is needed beyond running Chrome with Chromecast functionality active. Verified public proof-of-concept code is not available at the time of publication.

Refer to Chromium Issue #520172356 for upstream technical details as they become public.

Detection Methods for CVE-2026-16416

Indicators of Compromise

Chrome renderer or utility processes spawning unexpected child processes after receiving mDNS or Chromecast SSDP traffic
Unexplained crashes in Chrome processes handling Cast components, particularly with heap corruption signatures
Anomalous outbound connections from Chrome broker processes following inbound multicast traffic on UDP 1900 or 5353

Detection Strategies

Inventory installed Chrome versions across the fleet and flag any build below 150.0.7871.182
Monitor for Chrome crash reports referencing Cast, mDNS, or media router modules
Inspect local network traffic for malformed Chromecast discovery or DIAL protocol payloads with abnormal length fields

Monitoring Recommendations

Enable Chrome enterprise crash reporting and correlate crashes with recent network activity
Alert on process lineage anomalies where Chrome spawns non-standard children such as command interpreters
Track version drift on managed endpoints and prioritize hosts on shared or untrusted networks

How to Mitigate CVE-2026-16416

Immediate Actions Required

Update Google Chrome to version 150.0.7871.182 or later on all managed endpoints
Restart browser instances after patch deployment to load the fixed Chromecast binary
Restrict endpoints on untrusted or shared Wi-Fi networks from processing Chromecast discovery traffic until patched

Patch Information

Google released the fix in the Chrome Stable Channel update announced in the Chrome Releases blog. Chromium-based browsers should pick up the upstream fix in subsequent releases. Verify patch application by checking chrome://version and confirming the build is 150.0.7871.182 or higher.

Workarounds

Disable the Cast feature via the enterprise policy EnableMediaRouter=false where Chromecast is not required
Segment corporate endpoints from guest and IoT VLANs that host Chromecast devices
Block inbound multicast DNS (UDP 5353) and SSDP (UDP 1900) on endpoint host firewalls when Cast is not needed

bash

# Configuration example - disable Media Router via Chrome enterprise policy (Linux)
sudo mkdir -p /etc/opt/chrome/policies/managed
cat <<EOF | sudo tee /etc/opt/chrome/policies/managed/disable_cast.json
{
  "EnableMediaRouter": false,
  "MediaRouterCastAllowAllIPs": false
}
EOF