Threat Intelligence / CVE / CVE-2026-87491

CVE-2026-87491 — Google Chrome

CISA KEV

CVSS v3.1 8.8 (HIGH) · EPSS 3.1% (higher than 87.4% of all scored CVEs) · Priority 9/10 · Published 2026-09-09

As of 2026-09-21, CVE-2026-87491 is a HIGH-severity vulnerability in Google Chrome, CVSS v3.1 8.8, EPSS 3.1% (87.4th percentile). It is listed in the CISA Known Exploited Vulnerabilities catalog (added 2026-09-09), with a US federal remediation deadline of 2026-09-23. Threadlinqs Intelligence links 1 tracked threat campaign to CVE-2026-87491, most recently “UTA0565 Chains Chrome and Windows Zero-Days (CVE-2026-85046, CVE-2026-87491, CVE-2026-85880) to Deploy CLEANGULP Malware”.

Last updated: 2026-09-21

What is CVE-2026-87491?

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)

The record classifies CVE-2026-87491 under weakness class CWE-787. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs a user to take an action first, and has high impact on confidentiality, integrity, availability. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 18 days ago.

Severity and exploitation probability

CVSS v3.1 base score: 8.8 — HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS (FIRST): 3.1% probability of exploitation in the next 30 days, higher than 87.4% of all scored CVEs
CISA KEV: Listed since 2026-09-09, federal remediation deadline 2026-09-23
Threadlinqs priority: 9/10 — CISA KEV-listed, which Threadlinqs floors at 9
Published: 2026-09-09, last modified 2026-09-21

Is CVE-2026-87491 being exploited?

CISA added CVE-2026-87491 to the Known Exploited Vulnerabilities catalog on 2026-09-09, which means the agency holds evidence of exploitation in the wild; US federal civilian agencies had to remediate it by 2026-09-23 under BOD 22-01. Weaponised exploit code for CVE-2026-87491 is publicly available. 2 public proof-of-concept repositories are tracked for this identifier. It currently carries a trending score of 65 in the Threadlinqs vulnerability feed.

SneakyNachos/CVE-2026-87491-and-CVE-2026-85046-the-bagel-fell-off-the-counter (github)
trickest/cve (trickest)

Affected products and versions

Google: Chrome

How to fix CVE-2026-87491

Vendor advisory: https://chromereleases.googleblog.com/2026/09/stable-channel-update-for-desktop_0808145027.html. Because CVE-2026-87491 is KEV-listed, US federal civilian agencies were required to apply the vendor fix, or stop using the product, by 2026-09-23. Apply the vendor fix referenced above to every affected product listed in this record, then confirm the running version against the vendor advisory.

Threat activity tracking CVE-2026-87491

1 tracked threat in the Threadlinqs corpus references CVE-2026-87491, either in the campaign’s CVE list or as an indicator on the campaign record.

UTA0565 Chains Chrome and Windows Zero-Days (CVE-2026-85046, CVE-2026-87491, CVE-2026-85880) to Deploy CLEANGULP Malware — CRITICAL · 2026-09-27

Sources

Enriched from CVE.org, NVD, FIRST EPSS, CISA KEV, GitHub Security Advisories, public proof-of-concept repositories. Last verified by Threadlinqs on 2026-09-27. This product uses the NVD API but is not endorsed or certified by the NVD.

Other references

Full detection coverage & IOCs for threats exploiting CVE-2026-87491 are available via the Threadlinqs MCP server (Purple tier). View plans →

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