CriticalCVE-2018-6065

    Google Chromium V8 Integer Overflow Vulnerability (CVE-2018-6065)

    Published In CISA KEV since Sources: CVE.org

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    What is affected, what to do

    Integer overflow in computing the required allocation size when instantiating a new javascript object in V8 in Google Chrome prior to 65.0.3325.146 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page.

    The vulnerability is being actively exploited; treat it as a priority. Update Google Chrome to version 65.0.3325.146. Immediate actions, mitigation and detection rules are in the runbook below.

    Affected
    • Google Chrome lt *..65.0.3325.146
    Fixed in
    • Google Chrome 65.0.3325.146

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

    Metrics

    8.8

    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: CVE.org

    60.3 %

    EPSS score

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

    Source: FIRST EPSS, percentile 99.16

    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
    222.66 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
    60.3 %
    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
    99.16
    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-190

    Response and mitigation

    Why act now?

    Prioritisation rationale

    This is a network-reachable, unauthenticated memory-corruption bug in V8 that needs only a visit to a crafted page, delivered via phishing link, watering hole or malvertising. That makes it classic first-stage material for renderer-exploit plus sandbox-escape chains. Exploitation likelihood is very high, while CISA does not flag known ransomware use. Because the fix has been available since 2018, any hit in your estate is first and foremost a patch- and asset-management finding that exposes shadow IT, EoL systems or stale embedded engines. Treat such hosts as critical, and give top priority to internet-facing user endpoints and admin workstations.

    1. Runbook step 1

      Immediate response (0-24 h)

      • Inventory first: Query your asset and EDR inventory for any Chromium-based browser (Google Chrome, Microsoft Edge, Opera, Linux Chromium packages) running a release older than Chrome 65.0.3325.146 or its V8 equivalent. Any hit means the browser has gone years without updates, which typically points to broken auto-update or an abandoned host.
      • Patch: Update Google Chrome to at least 65.0.3325.146, and in practice to current Stable, because many later V8 bugs have also landed on KEV. For Edge, Opera and other derivatives, the patch is available from the vendor — look up the exact version in the vendor advisory.
      • Linux: On Debian 9, update the chromium package through Debian security updates. Red Hat Enterprise Linux 6 (Desktop/Server/Workstation) is end-of-life, so either remove Chromium or isolate the host. Look up the specific erratum ID in the vendor advisory.
      • Mobile: Use MDM to locate the Xiaomi Mi6 Browser and other OEM Chromium forks on managed devices. If no update exists, block the app and move users to a maintained browser.
      • Embedded engines: Identify Electron, CEF and WebView-based business applications that ship 2018-era or older V8. Push the vendor for an update and restrict those apps to trusted content in the meantime.

    2. Runbook step 2

      Mitigation layers

      • Configuration management: Enforce auto-update through GPO or Intune. For Chrome, set the ADMX policies UpdateDefault and AutoUpdateCheckPeriodMinutes, plus RelaunchNotification set to 2 with a short RelaunchNotificationPeriod, and apply the equivalent Edge policies. Remove any policy that freezes updates, such as UpdateDefault=0 or a pinned TargetVersionPrefix.
      • Engine hardening: Disable the V8 JIT for untrusted sites. In Chrome, use DefaultJavaScriptJitSetting=2 with exceptions in JavaScriptJitAllowedForSites; in Edge, set EnhanceSecurityMode to Strict. This significantly raises the bar for V8 memory-corruption exploits. Confirm that site isolation and the sandbox have not been disabled.
      • Network: On the web proxy or SWG, block newly registered domains, uncategorised sites, and known malvertising or exploit-kit categories. Fingerprint Chrome user agents below 65 at the proxy and deny internet egress until those hosts are remediated.
      • Segmentation: Move unpatchable legacy hosts, such as RHEL 6 machines or kiosk and HMI systems with embedded browsers, into a dedicated VLAN. Give that VLAN no internet egress and only an allowlist of internal destinations.
      • Endpoint and IAM: Run browsers under standard user rights with no local admin. Enable ASR rules or an EDR policy that restricts child processes spawned by browsers.

    3. Runbook step 3

      Detection rules

      • EDR/Sysmon EID 1 (process ancestry): Alert on browser processes spawning shells or LOLBins. KQL: DeviceProcessEvents | where InitiatingProcessFileName in~ ("chrome.exe","msedge.exe","opera.exe") | where FileName in~ ("cmd.exe","powershell.exe","rundll32.exe","mshta.exe","wscript.exe")
      • Sandbox tampering: Hunt for --no-sandbox, --disable-site-isolation-trials or --js-flags= in browser command lines outside documented developer or test hosts. Sigma shape: Image|endswith: '\chrome.exe' combined with CommandLine|contains: '--no-sandbox'.
      • Crash telemetry: Look for clusters of Windows Event ID 1000 (Application Error) or 1001 (WER) with faulting module chrome.dll or msedge.dll, and for renderer crash dumps in Crashpad directories. These are especially suspicious when several hosts crash after visiting the same domain.
      • Sysmon EID 11 / EID 3: Watch for browser processes writing executables outside download and cache paths, for example into %TEMP% or %APPDATA%. Also watch for browser child processes making direct outbound connections to rare destinations.
      • Proxy/Zeek HTTP logs: Report user agents matching Chrome/6[0-4]\. or Chrome/65\.0\.3325\.(?!14[6-9]|1[5-9]\d) to map vulnerable clients. This will not catch the exploit itself, but it shows your real attack surface.

    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

    Integer overflow in computing the required allocation size when instantiating a new javascript object in V8 in Google Chrome prior to 65.0.3325.146 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page.

    Source: cvelistv5, NVD (NIST), 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
    • < 65.0.3325.146
    • 65.0.3325.146
    googlechrome
    • < 65.0.3325.146
    • 65.0.3325.146
    mimi6_browser
    • —
    • —

    Vendors and products

    Affected operating systems

    Affected operating systems
    Linuxdebiandebian_linux9.0
    Linuxredhatenterprise_linux_desktop6.0
    Linuxredhatenterprise_linux_server6.0
    Linuxredhatenterprise_linux_workstation6.0

    Weakness classes (CWE)

    • CWE-190Integer Overflow or Wraparound

      Base

      The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.

      Entry at MITRE CWE-190

    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
    Exploit-DBEDB-ID 44584 (opens in a new tab)exploit-db.comPoC (publicly reported)reported, not verified—

    References & sources

    • crbug.com808192x_refsource_MISC, Exploit, Issue tracking
    • chromereleases.googleblog.com2018/03/stable-channel-update-for-desktop.htmlx_refsource_CONFIRM, Release notes, Vendor advisory
    • securityfocus.com103297Vulnerability database, x_refsource_BID, Broken link, Third-party advisory, Vulnerability database
    • access.redhat.comRHSA-2018:0484Vendor advisory, x_refsource_REDHAT, Third-party advisory
    • exploit-db.com44584Exploit, x_refsource_EXPLOIT-DB, Exploit, Third-party advisory, Vulnerability database
    • debian.orgDSA-4182Vendor advisory, x_refsource_DEBIAN, Mailing list, Third-party advisory
    • zerodayinitiative.comadvisories/ZDI-19-367x_refsource_MISC, Third-party advisory, Vulnerability database
    • cisa.govknown-exploited-vulnerabilities-catalog?field_cve=CVE-2018-6065government-resource, US government resource
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