# CVE-2026-87491 — Google Chrome **CISA KEV** > 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](https://cwe.mitre.org/data/definitions/787.html). 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](https://github.com/SneakyNachos/CVE-2026-87491-and-CVE-2026-85046-the-bagel-fell-off-the-counter) (github) - [trickest/cve](https://github.com/trickest/cve/blob/main/2026/CVE-2026-87491.md) (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](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](https://intel.threadlinqs.com/threat/TL-2026-2681) — 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** - [chromereleases.googleblog.com](https://chromereleases.googleblog.com/2026/09/stable-channel-update-for-desktop_0808145027.html) - [issues.chromium.org](https://issues.chromium.org/issues/543557673) Canonical: https://intel.threadlinqs.com/cve/CVE-2026-87491 Full detection coverage and IOCs for threats exploiting CVE-2026-87491 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp