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cve recordhighexploited in the wildzero day3 of 3 cataloguesexploit reported

CVE-2026-87491

Google · Chromium V8 · Google Chromium V8 Out of Bounds Write Vulnerability

· Added to CISA KEV
CVSS
Severityhigh
Weakness
EPSS0.86%56.5th percentile
Exploited3 KEV sources
Ransomware useUnknown
Federal fix dueSep 23, 2026
patch window

Called exploited 1 days before disclosure.

Measured from the CVE publication date to the earliest of 3 KEV catalogues that list it.

The life of this vulnerability

  1. CVE reserved
  2. CVE published1d
  3. First KEV listing1d
  4. Last KEV listing1d
  5. Last sightingsame day

Gaps are compressed to equal steps. The elapsed time is printed under each.

Which catalogues call it exploited

Sources3 of 3
Listings differ by1 d
Strongest claimconfirmed

3 catalogues list it. CIRCL aggregates the others and is shown but not counted.

Public exploitation evidence

2 public reports collected from VulnCheck and CIRCL, first on Sep 8, 2026. Each links to its original source. We have not verified them.

Description

Google Chromium V8 contains an out of bounds write vulnerability that allows a remote attacker to execute arbitrary code inside the sandbox via a crafted HTML page. This vulnerability could affect multiple web browsers that utilize Chromium, including, but not limited to, Google Chrome, Microsoft Edge, and Opera.

Required action (CISA)

Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

References

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Our coverage of CVE-2026-87491

CVE-2026-87491high

Chrome V8 Zero-Day Exploited in the Wild Enables Code Execution Inside Sandbox

Google on Thursday released updates to patch 230 security vulnerabilities, including one that has come under active exploitation in the wild. The medium-severity vulnerability, assigned the CVE identifier CVE-2026-87491 (CVSS score: N/A), has been described as an out-of-bounds bug in V8, Chrome's JavaScript and WebAssembly engine. "Out-of-bounds write in V8 in Google Chrome prior to