CriticalCVE-2026-11645

    Google Chromium V8 Out-of-Bounds Read and Write Vulnerability (CVE-2026-11645)

    Published Last modified In CISA KEV since Sources: pwn.watch, Debian, Msrc Update Guide, CVE.org, BSI, Palo Alto Networks

    What is affected, what to do

    Out of bounds read and write in V8 in Google Chrome prior to 149.0.7827.103 allowed a remote attacker to execute arbitrary code inside a sandbox via a crafted HTML page. (Chromium security severity: High)

    The vulnerability is being actively exploited; treat it as a priority. The available sources name no fixed version. Check the vendor guidance in the references below. Immediate actions, mitigation and detection rules are in the runbook below.

    Conflicting version data — version display is hidden until the data is resolved.

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    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: pwn.watch, Debian, Msrc Update Guide, CVE.org, BSI, Palo Alto Networks

    2.4 %

    EPSS score

    Moderate — model estimates 1-10% exploitation likelihood.

    Source: FIRST EPSS, percentile 84.3

    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
    219.40 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 exploitedSource: VulnCheck KEV (opens in a new tab) How we classify
    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
    2.4 %
    Moderate — model estimates 1-10% exploitation likelihood.
    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
    84.3
    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 8 June 2026
    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-125, CWE-787

    Response and mitigation

    Why act now?

    Prioritisation rationale

    This flaw is network-reachable without authentication and needs only a page visit, which attackers trivially obtain through watering-hole sites, malvertising or phishing links. On its own it yields code execution inside the renderer sandbox, but in practice V8 bugs like this are chained with a separate sandbox escape to compromise selected individuals such as executives, administrators or journalists. CISA does not flag ransomware use, and exploitation likelihood is clearly above average but not in the very top tier. Because the browser runs on virtually every endpoint and the patch is low-risk, treat this as "high – remediate within 24-72 h", and as immediate for privileged or OT-adjacent systems.

    1. Runbook step 1

      Immediate response (0-24 h)

      • Update Google Chrome to 149.0.7827.103 or later. Force the update centrally via GPO/Intune/MDM (Google Update policy UpdateDefault or the per-app Update{8A69D345-D564-463C-AFF1-A69D9E530F96} set to automatic). Verify the result from software inventory or EDR telemetry, not user self-reporting.
      • Force a browser relaunch. The fix only takes effect after a restart. Set RelaunchNotification = 2 (required) and RelaunchNotificationPeriod (e.g. 3600000 ms) so long-lived sessions don't keep the vulnerable V8 build in memory for weeks.
      • Cover every Chromium-based browser and runtime: Microsoft Edge, Opera, Brave, Vivaldi, plus Electron/CEF apps that embed V8. Patches are available from each vendor — look up the fixed version in the respective vendor advisory (for Edge: Microsoft Security Update Guide / Edge release notes).
      • Pull a non-compliance list. Use KQL DeviceTvmSoftwareInventory | where SoftwareName has "chrome" | where parse_version(SoftwareVersion) < parse_version("149.0.7827.103") and raise tickets to endpoint management with a sub-24 h SLA.
      • Patch high-value users first: admins, executives, finance and OT engineering workstations (including jump hosts with browsers). Block internet browsing from these systems until the patch is verified.
      • Check sandbox integrity. Hunt for browser processes launched with --no-sandbox or --disable-site-isolation-trials. Without the sandbox, renderer code execution becomes direct host compromise.

    2. Runbook step 2

      Mitigation layers

      • Configuration / browser hardening: Disable the V8 JIT with policy DefaultJavaScriptJitSetting = 2 (on Edge, set Enhanced Security Mode to "Strict"). Allow-list business apps via JavaScriptJitAllowedForSites. This sharply reduces the V8 memory-corruption attack surface at some performance cost.
      • Enforce Site Isolation: Set SitePerProcess = 1 and confirm no policy disables it. This limits what a compromised renderer can reach across origins.
      • Network / web proxy: Block or isolate (Remote Browser Isolation) the "Newly Registered Domains", "Uncategorized" and "Malvertising" categories. With TLS inspection in place, detect outdated browsers via the Sec-CH-UA-Full-Version-List client hint and redirect them to a remediation page. The reduced User-Agent string is not reliable for this.
      • Endpoint hardening: Use EDR or application control (WDAC/AppLocker) to block child processes of chrome.exe/msedge.exe such as cmd.exe, powershell.exe, mshta.exe, rundll32.exe and regsvr32.exe. This breaks common post-sandbox-escape chains.
      • IAM / least privilege: Remove local admin rights from clients and run privileged work on dedicated PAWs with no internet browser, to cap the blast radius.
      • Segmentation: Give OT and critical-infrastructure control networks no direct web access. Reach vendor portals only through a hardened, patched terminal server.

    3. Runbook step 3

      Detection rules

      • EDR process ancestry (Sysmon EID 1 / MDE): Alert on a shell or LOLBin spawned by a browser: DeviceProcessEvents | where InitiatingProcessFileName in~ ("chrome.exe","msedge.exe","opera.exe") | where FileName in~ ("cmd.exe","powershell.exe","wscript.exe","mshta.exe","rundll32.exe","regsvr32.exe"). Exclude only known download handlers.
      • File artefacts (Sysmon EID 11): Flag browser processes writing .exe, .dll, .ps1, .hta or .lnk outside Downloads/cache paths, e.g. %APPDATA%, %TEMP% or Startup. Sigma shape: Image|endswith: '\chrome.exe' AND TargetFilename|endswith: ['.exe','.dll','.ps1'] AND NOT TargetFilename|contains: '\Downloads\'.
      • Renderer crash clusters: Repeated renderer (--type=renderer) crashes on one host shortly after visiting a new domain suggest failed exploit attempts. Look for new dumps under ...\User Data\Crashpad\reports and, if enabled, WER Event ID 1000/1001, then correlate with proxy logs.
      • Network telemetry (Zeek/Suricata/proxy): Watch for first-seen young domains reached via ad-network redirect chains, immediately followed by anomalous egress from the same host. Examples include periodic beaconing or direct-to-IP connections with no preceding DNS lookup. Also enable vendor-feed Suricata signatures for Chromium exploit kits.
      • Compliance detection: Produce a daily report of browsers below 149.0.7827.103. Raise alert severity for any vulnerable host that also has internet egress.

    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

    Out of bounds read and write in V8 in Google Chrome prior to 149.0.7827.103 allowed a remote attacker to execute arbitrary code inside a sandbox via a crafted HTML page. (Chromium security severity: High)

    Source: pwn.watch, Debian Security Advisories, Microsoft Security Update Guide, cvelistv5, CISA KEV Catalog, NVD (NIST), CVE.org (MITRE), BSI CSAF, BSI WID Portal, paloalto_rss

    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
    • < 149.0.7827.103
    • 149.0.7827.103
    googlechrome
    • < 149.0.7827.103
    • 149.0.7827.103

    Vendors and products

    Affected operating systems

    Affected operating systems
    Linuxdebianchromiumbookworm
    Linuxdebianchromiumtrixie

    Weakness classes (CWE)

    • CWE-125Out-of-bounds Read

      Base

      The product reads data past the end, or before the beginning, of the intended buffer.

      Entry at MITRE CWE-125

    • CWE-787Out-of-bounds Write

      Base

      The product writes data past the end, or before the beginning, of the intended buffer.

      Entry at MITRE CWE-787

    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
    PoC-in-GitHub (nomi-sec)CVE-2026-11645 (opens in a new tab)github.comPoC (publicly reported)reported, not verified
    PoC-in-GitHub (nomi-sec)CVE-2026-11645-Out-of-bounds-Read-Write (opens in a new tab)github.comPoC (publicly reported)reported, not verified

    References & sources

    Changes to this CVE

    Who changed this CVE and when: NVD (analysis, affected products, CVSS), the CVE publisher (CNA) and additional providers such as CISA (ADP).

    1. ReceivedGoogle Chrome

      Description added or changed

      Show 3 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Descriptionadded
      —
      Out of bounds read and write in V8 in Google Chrome prior to 149.0.7827.103 allowed a remote attacker to execute arbitrary code inside a sandbox via a crafted HTML page. (Chromium security severity: High)
      Referenceadded
      —
      https://chromereleases.googleblog.com/2026/06/stable-channel-update-for-desktop_0153744567.html
      Referenceadded
      —
      https://issues.chromium.org/issues/506689381

      Source identifier: chrome-cve-admin@google.com

    One NVD translation into another language is hidden.

    Linked advisories

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    Badge preview for CVE-2026-11645
    <a href="https://intel.neosec.eu/en/cve/CVE-2026-11645"><img src="https://intel.neosec.eu/badge/cve/CVE-2026-11645.svg?lang=en" alt="CVE-2026-11645 – NEOSEC Intel" height="20"></a>