Cyber Resilience

CVE-2026-5866

High

Published: 08 April 2026

Published
08 April 2026
Modified
13 April 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 0.0030 21.8th percentile
Risk Priority 55 floored blend · peak EPSS

Summary

CVE-2026-5866 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 21.8th 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-16 (Memory Protection) and SI-2 (Flaw Remediation).

Deeper analysis

CVE-2026-5866 is a use-after-free vulnerability (CWE-416) in the Media component of Google Chrome prior to version 147.0.7727.55. Published on 2026-04-08, 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 via a crafted HTML page, enabling arbitrary code execution inside the Chrome sandbox. Exploitation requires user interaction, such as visiting the malicious page, but needs no privileges and has low attack complexity over the network.

Google addressed the issue in the stable channel update to Chrome 147.0.7727.55. Additional details are available in the Chrome Releases blog at https://chromereleases.googleblog.com/2026/04/stable-channel-update-for-desktop.html and the Chromium issue tracker at https://issues.chromium.org/issues/492218537.

EU & UK References

Vulnerability details

Use after free in Media in Google Chrome prior to 147.0.7727.55 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?

CVE-2026-5866 is a client-side use-after-free vulnerability in Chrome exploited via crafted HTML pages, directly enabling drive-by compromise (T1189) and exploitation for client execution (T1203).

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

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CVE-2026-7352Same product: Apple Macos

Affected Assets

google
chrome
≤ 147.0.7727.55

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

SI-2 Flaw Remediation good match
prevent

Directly remediates the use-after-free vulnerability by requiring timely identification, reporting, and correction via the Chrome patch to version 147.0.7727.55.

SI-16 Memory Protection good match
prevent

Implements memory protection controls such as ASLR and DEP to minimize the exploitability of use-after-free flaws in the Chrome Media component.

SC-39 Process Isolation partial match
prevent

Enforces process isolation through Chrome's sandboxing, confining arbitrary code execution from the vulnerability to the isolated media process.

References