Google Chrome: Improper input validation in FileAPI
Summary
Improper input validation in the FileAPI component of Google Chrome desktop allows a remote attacker to potentially execute arbitrary code inside the browser sandbox. The attacker must lure a user to a crafted HTML page, and no authentication is required. Chromium rates the flaw Critical, and no known exploitation was reported at the time of the sources.
Affected
- Google Chrome desktop prior to 156.0.8078.73
- The NVD/CNA affected range in the CVE data is inconsistent ("156.0.8078.73 to < 156.0.8078.73"); the vendor description states "prior to 156.0.8078.73"
Fixed in
- Google Chrome 156.0.8078.73 or later (Stable Channel Update of 27 October 2026, per secondary reports)
- Later desktop builds reportedly exist; install the latest stable release
- Unknown whether Chromium-based products such as Microsoft Edge have released matching fixes
Workaround
- Unknown. No vendor workaround was found; updating is the fix.
Exploitation
- CISA SSVC: exploitation none, automatable no, technical impact total
- Not listed in CISA KEV at the time of the search
- No public proof of concept found; no evidence of exploitation in the wild reported as of 26 October 2026
- EPSS: 0.34 % per the CVE data (other sources list 0.24 %)
Our recommendation
- Check the Chrome version on all endpoints and update to the latest stable release
- Confirm auto-update is enabled and restart browsers after updating
- Managed fleets: verify that the update policy is actually applied
- Check Microsoft Edge and other Chromium-based browsers for matching updates
- Monitor the vendor advisory and CISA KEV for changes
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Chrome Releases: Stable Channel Update for Desktop chromereleases.googleblog.com
- Chromium issue tracker 572193211 issues.chromium.org
- CVE-2026-118331 CVE Threat Intelligence cve.threatint.com
- OffSeq Radar: CVE-2026-118331 radar.offseq.com
- Malwarebytes: Chrome and Firefox updates fix serious security flaws www.malwarebytes.com
- Sandbanks Digital: Chrome security update October 2026 sandbanksdigital.com
- Piunika Web: Google Chrome 156 security update piunikaweb.com
- GitHub astruzocyber/CVE issue 3399 github.com
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 31 Oct 2026, 09:57.
Original description (NVD)
Improper input validation in FileAPI in Google Chrome prior to 156.0.8078.73 allowed a remote attacker to potentially execute arbitrary code inside the sandbox via a crafted HTML page. (Chromium security severity: Critical)
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
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