CriticalCVE-2023-5217

    Google Chromium libvpx Heap Buffer Overflow Vulnerability (CVE-2023-5217)

    Published In CISA KEV since Sources: SingCERT, Debian, pwn.watch, CVE.org, OSV, Schneider Electric

    Share

    What is affected, what to do

    Heap buffer overflow in vp8 encoding in libvpx in Google Chrome prior to 117.0.5938.132 and libvpx 1.13.1 allowed a remote attacker to potentially exploit heap corruption 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.

    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, Debian, pwn.watch, CVE.org, OSV, Schneider Electric

    49.0 %

    EPSS score

    Elevated — model estimates 10-50% exploitation likelihood.

    Source: FIRST EPSS, percentile 98.9

    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
    225.71 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: CSA/SingCERT 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
    49.0 %
    Elevated — model estimates 10-50% 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
    98.9
    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 15 November 2023
    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-787

    Response and mitigation

    Why act now?

    Prioritisation rationale

    This flaw was exploited as a zero-day in an exploit chain. It is network-reachable, needs no authentication and only requires the victim to load a crafted page. It yields code execution in the renderer and typically serves as stage one before a sandbox escape. Its exploitation likelihood is among the highest of any tracked CVE, and CISA does not flag ransomware use. The pattern fits targeted operations against individuals with access to sensitive information, so prioritise executives, admins and mobile devices. Because browsers sit on virtually every endpoint and the fix is trivial to roll out, treat closure within 24–72 hours as a high-priority action. Track slower-moving Electron apps and Linux libvpx consumers as follow-up items.

    1. Runbook step 1

      Immediate response (0-24 h)

      • Push Chrome to 117.0.5938.132 or later fleet-wide. Via GPO/Intune/Jamf, set RelaunchNotification = 2 (required) and a short RelaunchNotificationPeriod. Confirm no TargetVersionPrefix pin holds endpoints on an older build. Updates only take effect after a browser restart, so force-close stale sessions.
      • Inventory and patch every other Chromium derivative and libvpx consumer. This covers Microsoft Edge, Brave, Opera, Vivaldi, Electron-based desktop apps (chat and meeting clients) and Firefox. Patches are available from each vendor — look up the fixed version in the vendor advisory.
      • Enforce iOS/iPadOS 17.0.3 via MDM. Flag devices on 17.0–17.0.2 as non-compliant. The context lists 16.7 as affected without a fix version; check Apple's security advisory for the patched 16.x release and treat those devices as elevated risk until updated.
      • Update libvpx on Linux. On Debian 10/11 and on any servers or workstations shipping libvpx (transcoding pipelines, ffmpeg, WebRTC gateways), upgrade to libvpx 1.13.1 or the distro's fixed package. Look up the Debian DSA/DLA with the vendor. Check the current state with dpkg -l 'libvpx*'.
      • Patch high-exposure users first. Start with executives, admins, legal/PR and frequent travellers, and warn them about unsolicited links arriving via messengers, SMS and email.

    2. Runbook step 2

      Mitigation layers

      • Browser configuration: Enforce SitePerProcess = true and surface outdated browsers through Chrome Enterprise reporting or Edge management. Where the business allows, restrict camera and microphone access to an allowlist (VideoCaptureAllowedUrls, AudioCaptureAllowedUrls). This narrows VP8 encoding paths via WebRTC/MediaRecorder but is not a full fix.
      • Network/proxy: At the secure web gateway, block or redirect Chrome user agents below 117.0.5938.132 to an update notice. Deny newly registered and uncategorised domains for standard users, since exploit chains are typically delivered from short-lived landing pages.
      • Endpoint hardening: Enable EDR/ASR behaviour rules that block browsers from spawning shells or script hosts. This makes the follow-on sandbox-escape and payload stage harder.
      • Mobile: Evaluate iOS Lockdown Mode for high-risk staff. Use conditional access to cut non-compliant iOS devices off from mail and SaaS.
      • IAM/least privilege: No browsing with privileged accounts. Move admin work onto dedicated, internet-restricted privileged access workstations (PAWs).

    3. Runbook step 3

      Detection rules

      • EDR process ancestry (Sysmon EID 1 / Defender): Flag a browser spawning a shell or LOLBin, e.g. in KQL: DeviceProcessEvents | where InitiatingProcessFileName in~ ("chrome.exe","msedge.exe","brave.exe") and FileName in~ ("cmd.exe","powershell.exe","pwsh.exe","wscript.exe","mshta.exe","rundll32.exe").
      • Vulnerability inventory: Find exposed hosts with DeviceTvmSoftwareInventory | where SoftwareName has "chrome", comparing versions with parse_version(SoftwareVersion) < parse_version("117.0.5938.132"); plain string comparison is unreliable for version numbers. On Linux, catch outdated libvpx packages through package inventory or the vulnerability scanner.
      • Crash telemetry: Look for bursts of renderer crashes — Crashpad dumps or Windows Event ID 1000 for chrome.exe with media/VP8 module involvement — and correlate them with the URL visited just before in proxy logs. Failed heap exploitation attempts often leave exactly this trail.
      • Proxy/Zeek: Flag user agents matching Chrome/117.0.5938.(0-131) or older major versions that hit low-reputation domains or domains registered less than 30 days ago. Sigma shape: logsource: proxy, c-useragent|re: 'Chrome/1(0[0-9]|1[0-6])\.' plus a reputation enrichment.
      • File system (Sysmon EID 11): Alert on executables or DLLs written by a browser process outside its download and cache paths.

    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

    Heap buffer overflow in vp8 encoding in libvpx in Google Chrome prior to 117.0.5938.132 and libvpx 1.13.1 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page. (Chromium security severity: High)

    Source: CSA/SingCERT, Debian Security Advisories, pwn.watch, NVD (NIST), OSV (Open Source Vulnerabilities), cvelistv5, CISA KEV Catalog, CVE.org (MITRE), schneider_csaf

    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
    • < 117.0.5938.132
    • 117.0.5938.132
    Googlelibvpx
    • < 1.13.1
    • 1.13.1
    googlechrome
    • < 117.0.5938.132
    • 117.0.5938.132
    microsoftedge
    • 116.0.1938.98
    • 117.0.2045.47
    • —
    • —
    microsoftedge_chromium
    • 116.0.5845.229
    • 117.0.5938.132
    • —
    • —
    mozillafirefox
    • < 115.3.1
    • < 118.0.1
    • < 118.1
    • 115.3.1
    • 118.0.1
    • 118.1
    mozillathunderbird
    • < 115.3.1
    • 115.3.1
    webmprojectlibvpx
    • < 1.13.1
    • 1.13.1
    Schneider ElectricEcoStruxure™ Power Operation (EPO)
    • 2022 CU7
    • 2024 CU2
    • —
    • —

    Vendors and products

    Affected operating systems

    Affected operating systems
    Linuxdebianchromiumbookworm
    Linuxdebianchromiumbullseye
    Linuxdebiandebian_linux10.0
    Linuxdebiandebian_linux11.0
    Linuxdebiandebian_linux12.0
    Linuxredhatenterprise_linux9.0
    Linuxdebianfirefox-esrbullseye
    Linuxdebianlibvpxbookworm
    Linuxdebianlibvpxbullseye
    Linuxdebianthunderbirdbookworm
    Linuxdebianthunderbirdbullseye
    Mobileappleiphone_os16.7
    Mobileappleiphone_os—
    Otherfedoraprojectfedora37
    Otherfedoraprojectfedora38
    Otherfedoraprojectfedora39
    Otherappleipados16.7
    Otherappleipados—

    Weakness classes (CWE)

    • 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
    CSA/SingCERTActive Exploitation of Zero-Day Vulnerability in Apple Products (opens in a new tab)CSA/SingCERTactively exploited
    CSA/SingCERTActive Exploitation of Zero-Day Vulnerability in Google Chrome (opens in a new tab)CSA/SingCERTactively exploited

    References & sources

    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-2023-5217
    <a href="https://intel.neosec.eu/en/cve/CVE-2023-5217"><img src="https://intel.neosec.eu/badge/cve/CVE-2023-5217.svg?lang=en" alt="CVE-2023-5217 – NEOSEC Intel" height="20"></a>