CriticalCVE-2020-6418

    Google Chromium V8 Type Confusion Vulnerability (CVE-2020-6418)

    Published In CISA KEV since Sources: SingCERT, CVE.org

    What is affected, what to do

    This vulnerability allows a remote attacker to exploit a type confusion in the V8 engine of Google Chromium, leading to heap corruption via a crafted HTML page. It affects multiple browsers based on Chromium, including Google Chrome, Microsoft Edge, and Opera. The vulnerability is actively exploited in ransomware campaigns. Affected products include Google Chrome versions prior to 80.0.3987.122 and various Linux distributions such as Fedora and Debian. Immediate patching to the latest version is strongly recommended to mitigate the risk.

    The vulnerability is being actively exploited; treat it as a priority. Update Google Chrome to version 80.0.3987.122. Immediate actions, mitigation and detection rules are in the runbook below.

    Affected
    • Google Chrome lt *..80.0.3987.122
    Fixed in
    • Google Chrome 80.0.3987.122

    Not sure whether and how you are affected? Ask a question about this vulnerability

    Metrics

    8.8

    Priority

    XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.

    Source: NVD, CVSS v3

    8.8

    CVSS v3

    Severity High on the scale from 0 to 10.

    Source: SingCERT, CVE.org

    78.8 %

    EPSS score

    High — model estimates ≥ 50% chance of real-world exploitation within 30 days.

    Source: FIRST EPSS, percentile 99.59

    Show all metrics
    Severity
    Critical
    Priority (0–325)

    The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?

    Read in glossary
    223.35 Methodology
    Exploit maturity

    An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.

    Read in glossary
    actively exploited
    XIEM Effective CVSS

    XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command.

    Read in glossary
    8.8 Methodology
    CVSS v3

    CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.

    Read in glossary
    8.8
    EPSS score

    The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“.

    Read in glossary
    78.8 %
    High — model estimates ≥ 50% chance of real-world exploitation within 30 days.
    EPSS percentile

    The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking.

    Read in glossary
    99.59
    Critical — this CVE ranks in the top fifth of all CVEs scored today (rank ≥ 80%).
    KEV status

    The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.

    Read in glossary
    Actively exploited
    Published
    In CISA KEV since

    The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.

    Read in glossary
    CISA assessment (SSVC)
    Exploitation: active · not automatable · Technical impact: total
    Source: CISA Vulnrichment, as of 29 January 2025
    CWE

    CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect.

    Read in glossary
    CWE-843

    Response and mitigation

    Why act now?

    Prioritisation rationale

    The flaw is network-reachable without authentication and only requires the user to load a crafted page, delivered through phishing links, malvertising or watering-hole sites. It was originally exploited as a zero-day and sits among the CVEs with very high exploitation likelihood, though CISA does not flag known ransomware use. The fix shipped years ago, so any vulnerable instance today mainly signals broken patch management, typically on end-of-life Linux hosts, OT-adjacent kiosk or HMI systems, or applications with embedded Chromium. Treat such findings as high priority wherever the asset can reach the internet. For air-gapped segments without web access, medium priority with a documented migration plan is defensible.

    1. Runbook step 1

      Immediate response (0-24 h)

      • Enforce patch level: Bring Google Chrome on every endpoint to at least 80.0.3987.122. Since this build is long outdated, every install should realistically be on current Stable. Run an inventory query via EDR or software distribution (Intune, SCCM, Jamf) and flag anything below that baseline as a critical deviation.
      • Cover other Chromium browsers: Microsoft Edge (Chromium), Opera, Brave, Vivaldi and Linux Chromium packages are affected too. The fixed Edge and Opera builds are listed in each vendor's advisory. Look up the version there and reconcile it against your inventory.
      • Update Linux distributions: On Debian 9/10, Fedora 30/31 and RHEL 6 Desktop/Server, update the Chromium packages through distro repositories (apt, dnf, yum). Package versions are listed in the relevant DSA, FEDORA and RHSA notices; check the vendor advisory for exact versions. RHEL 6 and Debian 9 are end-of-life: schedule migration and isolate these hosts until then.
      • Inventory embedded Chromium runtimes: Electron and CEF-based apps (kiosks, HMI front-ends, thin clients, line-of-business tools) ship their own V8. Query the vendors and cut internet access for devices running stale runtimes.
      • Force restarts: Chrome only applies updates after a browser relaunch. Enforce this with RelaunchNotification=2 and a short RelaunchNotificationPeriod, and verify it through your software distribution tooling.

    2. Runbook step 2

      Mitigation layers

      • Configuration / update management: Audit the Google Update GPOs. UpdateDefault must not be disabled. Remove TargetVersionPrefix and rollback pinning unless a documented exception exists. Apply the same check to the Microsoft Edge Update policies.
      • Endpoint hardening: Never launch browsers with --no-sandbox or --disable-site-isolation-trials. Audit shortcuts and kiosk configs for these flags and enforce SitePerProcess=1. On current builds, disable JIT for high-risk user groups via DefaultJavaScriptJitSetting=2, which sharply reduces the attack surface for V8 type confusion bugs. In Edge, Enhanced security mode set to "Strict" does the same.
      • Network / web filtering: Block the "newly registered domains", "uncategorized" and "malvertising" categories at the proxy. Put admin workstations and jump hosts behind remote browser isolation, or remove web browsing from them entirely. A PAW has no business on the open web.
      • IAM / least privilege: Run browsers only under standard user accounts, never with local admin rights. Exploits for this bug are typically chained with a sandbox escape or local privilege escalation, so denying admin rights significantly limits the damage.
      • Application control: Use WDAC or AppLocker to block execution from %LOCALAPPDATA%\Temp and %USERPROFILE%\Downloads. This stops common second-stage payloads after a renderer compromise.

    3. Runbook step 3

      Detection rules

      • Process ancestry (Sysmon EID 1 / EDR): Detect shells and LOLBins spawned by browser processes. KQL: DeviceProcessEvents | where InitiatingProcessFileName in~ ("chrome.exe","msedge.exe","opera.exe") and FileName in~ ("cmd.exe","powershell.exe","rundll32.exe","mshta.exe","wscript.exe","regsvr32.exe"). Sigma shape: ParentImage|endswith: '\chrome.exe' combined with Image|endswith on the LOLBins above.
      • Renderer crashes: Clusters of chrome.exe crashes (Windows Event ID 1000/1001, Application Error, faulting module chrome.dll) shortly after visiting an external URL suggest failed exploit attempts. Correlate them with proxy logs on the same host within a ±2 min window.
      • File writes (Sysmon EID 11): Watch for browser child processes with --type=renderer in the command line writing executables (.exe, .dll, .ps1, .hta) outside the Chrome cache path. A sandboxed renderer should never do this.
      • Version drift as an indicator: Example SPL against inventory data: index=inventory product="Google Chrome" | eval v=split(version,".") | where tonumber(mvindex(v,0))<80 OR (tonumber(mvindex(v,0))=80 AND tonumber(mvindex(v,2))<3987). Every hit is an exposed host.
      • Network telemetry (Zeek/Suricata): Look for HTTP downloads of executables (files.log with mime_type=application/x-dosexec) that follow a visit to a rarely seen domain from the same client. Check conn.log against dns.log for new outbound connections from browser hosts to IPs with no preceding DNS resolution.

    Detection rules

    No NEOSEC detection rule is available for this vulnerability yet.

    Classification under NIS2 and CRA

    Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.

    NIS2

    NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.

    Read in glossary
    Actively exploited: treat the vulnerability as a priority in vulnerability handling under Art. 21(2)(e) NIS2. If it is exploited in your environment, check the reporting obligation under Art. 23 (early warning within 24 hours).
    CRA

    The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.

    Read in glossary
    Since 11.09.2026, manufacturers of affected products with digital elements must report actively exploited vulnerabilities under Art. 14 CRA, with an early warning within 24 hours via ENISA's single reporting platform.
    ISO/IEC 27001

    ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.

    Read in glossary
    Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.

    Description

    Type confusion in V8 in Google Chrome prior to 80.0.3987.122 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page.

    Source: CSA/SingCERT, NVD (NIST), cvelistv5, CISA KEV Catalog

    Affected products

    The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.

    Affected products
    Affected versionsFixed in
    GoogleChrome
    • < 80.0.3987.122
    • 80.0.3987.122
    googlechrome
    • < 80.0.3987.122
    • 80.0.3987.122

    Vendors and products

    Affected operating systems

    Affected operating systems
    Linuxdebiandebian_linux10.0
    Linuxdebiandebian_linux9.0
    Linuxredhatenterprise_linux_desktop6.0
    Linuxredhatenterprise_linux_server6.0
    Linuxredhatenterprise_linux_workstation6.0
    Otherfedoraprojectfedora30
    Otherfedoraprojectfedora31

    Weakness classes (CWE)

    • CWE-843Access of Resource Using Incompatible Type ('Type Confusion')

      Base

      The product allocates or initializes a resource such as a pointer, object, or variable using one type, but it later accesses that resource using a type that is incompatible with the original type.

      Entry at MITRE CWE-843

    Public exploit references

    Publicly reported proof-of-concepts, exploit modules and detection templates for this vulnerability. NEOSEC links to the original sources only and does not provide any exploit code.

    Public exploit references
    CISA KEV CatalogCISA Known Exploited Vulnerability (opens in a new tab)cisa.govactively exploited
    Packet StormGoogle Chrome 80 JSCreate Side Effect Type Confusion (opens in a new tab)packetstormsecurity.comPoC (publicly reported)reported, not verified—

    References & sources

    • chromereleases.googleblog.com2020/02/stable-channel-update-for-desktop_24.htmlx_refsource_MISC, Release notes, Vendor advisory
    • crbug.com1053604x_refsource_MISC, Exploit, Issue tracking, Patch, Vendor advisory
    • packetstormsecurity.comfiles/156632/Google-Chrome-80-JSCreate-Side-Effect-Type-Confusi…x_refsource_MISC, Exploit, Third-party advisory, Vulnerability database
    • access.redhat.comRHSA-2020:0738Vendor advisory, x_refsource_REDHAT, Third-party advisory
    • debian.orgDSA-4638Vendor advisory, x_refsource_DEBIAN, Mailing list, Third-party advisory
    • security.gentoo.orgGLSA-202003-08Vendor advisory, x_refsource_GENTOO, Third-party advisory
    • lists.fedoraproject.orgFEDORA-2020-f6271d7afaVendor advisory, x_refsource_FEDORA, Release notes
    • lists.fedoraproject.orgFEDORA-2020-39e0b8bd14Vendor advisory, x_refsource_FEDORA, Release notes
    • cisa.govknown-exploited-vulnerabilities-catalog?field_cve=CVE-2020-6418government-resource, US government resource
    Embed badge

    Show the severity and KEV status of this vulnerability on your site – with a link back here. The image is updated hourly.

    Badge preview for CVE-2020-6418
    <a href="https://intel.neosec.eu/en/cve/CVE-2020-6418"><img src="https://intel.neosec.eu/badge/cve/CVE-2020-6418.svg?lang=en" alt="CVE-2020-6418 – NEOSEC Intel" height="20"></a>