Cyber Resilience

CVE-2026-6303

High

Published: 15 April 2026

Published
15 April 2026
Modified
27 May 2026
KEV Added
—
Patch
—
CVSS Score v3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS Score 0.0037 28.7th percentile
Risk Priority 55 floored blend · peak EPSS

Summary

CVE-2026-6303 is a high-severity Use After Free (CWE-416) vulnerability in Google Chrome. Its CVSS base score is 8.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Drive-by Compromise (T1189); ranked at the 28.7th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified are NIST 800-53 SI-2 (Flaw Remediation) and RA-5 (Vulnerability Monitoring and Scanning).

Deeper analysis

CVE-2026-6303 is a use-after-free vulnerability (CWE-416) in the Codecs component of Google Chrome prior to version 147.0.7727.101. Published on 2026-04-15, it carries a CVSS v3.1 base score of 8.8 (AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H) and is classified as High severity by Chromium security.

A remote attacker can exploit this flaw by crafting an HTML page that triggers the use-after-free condition in Codecs, enabling arbitrary code execution within the browser's sandbox. Exploitation requires user interaction, such as visiting the malicious page, but needs no privileges or special access.

Mitigation is available via the Chrome stable channel update to version 147.0.7727.101 or later. Additional details are provided in the Chrome Releases blog post at https://chromereleases.googleblog.com/2026/04/stable-channel-update-for-desktop_15.html and the Chromium issue tracker at https://issues.chromium.org/issues/496282147.

EU & UK References

Vulnerability details

Use after free in Codecs in Google Chrome prior to 147.0.7727.101 allowed a remote attacker to execute arbitrary code inside a sandbox via a crafted HTML page. (Chromium security severity: High)

CWE(s)
CWE-416

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1189 Drive-by Compromise Initial Access
Adversaries may gain access to a system through a user visiting a website over the normal course of browsing.
attack.mitre.org →
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
attack.mitre.org →
Why these techniques?

Use-after-free in Chrome Codecs enables arbitrary code execution via crafted HTML page, directly facilitating drive-by compromise (T1189) and exploitation for client execution (T1203) with user interaction.

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0

CVEs Like This One

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CVE-2026-7342Same product: Apple Macos
CVE-2026-4680Same product: Apple Macos
CVE-2026-7355Same product: Apple Macos
CVE-2026-5284Same product: Apple Macos
CVE-2026-9992Same product: Apple Macos
CVE-2026-9118Same product: Apple Macos
CVE-2026-7336Same product: Apple Macos
CVE-2026-7974Same product: Apple Macos
CVE-2026-7352Same product: Apple Macos

Affected Assets

google
chrome
≤ 147.0.7727.101

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

SI-2 Flaw Remediation good match
prevent

Directly remediates the use-after-free vulnerability in Chrome's Codecs by requiring timely identification, reporting, and patching to version 147.0.7727.101 or later.

SI-16 Memory Protection partial match
prevent

Implements memory safeguards such as ASLR and non-executable memory that mitigate use-after-free exploitation by protecting against unauthorized access and code execution.

RA-5 Vulnerability Monitoring and Scanning partial match
preventdetect

Enables scanning to identify systems running vulnerable Chrome versions prior to 147.0.7727.101, facilitating prioritization and remediation.

References