CVE-2026-87491
Google Chromium V8 Out of Bounds Write Vulnerability
Google Chromium V8
Out of bounds write in V8 in Google Chrome prior to 153.0.8010.36 allowed a remote attacker to execute arbitrary code inside the sandbox via a crafted HTML page. (Chromium security severity: Medium)
Exploitation status
CISA Known Exploited Vulnerabilities
Listed by CISA on 9 September 2026. US federal agencies were required to remediate it by 23 September 2026.
EPSS — exploitation probability
FIRST puts the probability of exploitation activity in the next 30 days at 1%, which is higher than 61% of all scored vulnerabilities. EPSS is a forecast of activity, not a measure of severity, and it is rescored daily.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Frequently asked questions
Is CVE-2026-87491 being exploited by ransomware groups?
No ransomware group in this database is currently recorded as exploiting CVE-2026-87491.
What does CVE-2026-87491 affect?
CVE-2026-87491 affects Google Chromium V8. Out of bounds write in V8 in Google Chrome prior to 153.0.8010.36 allowed a remote attacker to execute arbitrary code inside the sandbox via a crafted HTML page. (Chromium security severity: Medium)
How severe is CVE-2026-87491?
CVE-2026-87491 is rated HIGH with a CVSS base score of 8.8. EPSS puts the probability of exploitation in the next 30 days at 1%, higher than 61% of all scored vulnerabilities. It is listed in the CISA Known Exploited Vulnerabilities catalog, with a federal remediation deadline of 23 September 2026.
How should organisations respond to CVE-2026-87491?
Apply the vendor patch for Google Chromium V8 as the first priority, and treat any internet-facing instance as the most urgent. Because this vulnerability is associated with ransomware activity, also review whether the affected systems were reachable before patching, rather than assuming that patching alone closes the incident.