CriticalCVE-2023-41993

    Apple Multiple Products WebKit Code Execution Vulnerability (CVE-2023-41993)

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

    What is affected, what to do

    The issue was addressed with improved checks. This issue is fixed in macOS Sonoma 14. Processing web content may lead to arbitrary code execution.

    The vulnerability is being actively exploited; treat it as a priority. Update Apple macOS to version 14. Immediate actions, mitigation and detection rules are in the runbook below.

    Affected
    • Apple macOS lt *..14
    Fixed in
    • Apple macOS 14

    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, Red Hat

    24.3 %

    EPSS score

    Elevated — model estimates 10-50% exploitation likelihood.

    Source: FIRST EPSS, percentile 97.9

    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
    224.09 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: Apple (CVE.org), 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
    24.3 %
    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
    97.9
    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 11 January 2024
    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-754

    Response and mitigation

    Why act now?

    Prioritisation rationale

    This flaw is reachable over the network without authentication and needs only the rendering of crafted web content. A single redirected HTTP request or a link is enough. It typically serves as the initial stage of an exploit chain that then escapes the sandbox and kernel protections to drop commercial surveillance tooling. Targeting is therefore selective — executives, political figures, journalists and civil society — rather than broad. CISA does not flag ransomware use, but exploitation likelihood is rated very high. Organisations with exposed individuals or frequent international travel should treat mobile-fleet patching as critical. Linux WebKitGTK hosts can generally follow a prompt but standard patch cycle.

    1. Runbook step 1

      Immediate response (0-24 h)

      • Update iOS/iPadOS to 17.0.1 and enforce it via MDM (Intune, Jamf, Workspace ONE). Devices that cannot move to iOS 17 must be on the 16.x security line at iOS 16.7 or later. Apple states that exploitation targeted versions before iOS 16.7.
      • Update macOS to Sonoma 14.0 or later. Older macOS releases receive a separate Safari/WebKit update; look up the exact version in Apple's security advisory.
      • Patch Linux hosts running WebKitGTK/WPE (Debian 11/12, Fedora 37/38). Run apt list --installed | grep -i webkit or rpm -qa | grep -i webkit, then apply the distribution security updates (DSA / Fedora update) for webkit2gtk/wpewebkit. Package versions are listed in the respective advisory.
      • Pull an MDM compliance report of all Apple devices below the fixed baseline. Prioritise high-risk users first: executives, legal, press/communications, admins, and staff travelling to high-risk regions.
      • Gate access with Conditional Access: block non-compliant devices from mail, VPN and SSO apps until they are updated.

    2. Runbook step 2

      Mitigation layers

      • Endpoint hardening (iOS/macOS): Enable Lockdown Mode for high-risk users. It disables JavaScript JIT and several complex web features, which sharply reduces WebKit attack surface.
      • Network/proxy: Force mobile traffic through always-on VPN or a secure web gateway, and block or upgrade plaintext HTTP. This blunts network-injection delivery, where an HTTP request is redirected to an exploit page. Add DNS filtering for newly registered and uncategorised domains.
      • Linux configuration: Remove WebKitGTK from servers and kiosks that don't need it. Where it is required, test disabling JIT (JSC_useJIT=false) and restrict embedded HTML renderers (mail clients, help viewers) to trusted content.
      • IAM/least privilege: Keep privileged admin sessions off mobile devices. Use short token lifetimes and phishing-resistant MFA (FIDO2) to limit the blast radius of a compromised handset.
      • Mail/messaging gateway: Enable URL rewriting and sandbox detonation for links. Block one-off links to freshly registered domains.

    3. Runbook step 3

      Detection rules

      • MDM inventory: Run a daily compliance query for OSVersion below 17.0.1 (iOS/iPadOS) or below 14.0 (macOS without the Safari update). KQL shape: IntuneDevices | where OS == "iOS" and OSVersion !startswith "17."
      • EDR process ancestry (macOS): Treat any child process of com.apple.WebKit.WebContent as highly suspicious — shells, curl, or unsigned binaries. KQL shape: DeviceProcessEvents | where InitiatingProcessFileName == "com.apple.WebKit.WebContent" | where FileName !in~ ("com.apple.WebKit.WebContent"). Also review clusters of WebContent crash reports (.ips in /Library/Logs/DiagnosticReports).
      • Linux auditd: Alert on execve events whose parent is WebKitWebProcess (Sigma: ParentImage|endswith: '/WebKitWebProcess' with Image|endswith in /sh, /bash, /python3). Baseline rule: -a always,exit -F arch=b64 -S execve -k webkit_exec.
      • iOS forensics: For suspected devices, run a backup or sysdiagnose through Amnesty's Mobile Verification Toolkit (MVT) against current public IOC sets. Look for unexpected process names in DataUsage.sqlite or in crash logs.
      • Network telemetry (Zeek/Suricata/proxy): Hunt for HTTP 302 redirects on plaintext sessions from mobile devices to unknown domains. Focus on short-lived domains hit once with a Safari user agent. Isolate the device immediately on a hit.

    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

    The issue was addressed with improved checks. This issue is fixed in macOS Sonoma 14. Processing web content may lead to arbitrary code execution. Apple is aware of a report that this issue may have been actively exploited against versions of iOS before iOS 16.7.

    Source: CSA/SingCERT, Debian Security Advisories, pwn.watch, NVD (NIST), OSV (Open Source Vulnerabilities), cvelistv5, CISA KEV Catalog, CVE.org (MITRE), redhat_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
    ApplemacOS
    • < 14
    • 14
    netappactive_iq_unified_manager
    • —
    • —
    netappcloud_insights_acquisition_unit
    • —
    • —
    netappcloud_insights_storage_workload_security_agent
    • —
    • —
    netapponcommand_insight
    • —
    • —
    netapponcommand_workflow_automation
    • —
    • —
    oraclegraalvm
    • 21.3.9
    • 20.3.13
    • —
    • —
    oraclejdk
    • 1.8.0
    • —
    oraclejre
    • 1.8.0
    • —
    webkitgtkwebkitgtk\+
    • < 2.42.2
    • 2.42.2
    Distribution and container packages (1)

    Downstream packages (e.g. Bitnami, Debian, Ubuntu, Red Hat). Versions refer to the distribution, not the vendor.

    Distribution and container packages
    Affected versionsFixed in
    bitnamijre
    • 1.9.0
    • —

    Vendors and products

    Affected operating systems

    Affected operating systems
    Linuxdebiandebian_linux11.0
    Linuxdebiandebian_linux12.0
    Linuxdebianwebkit2gtkbookworm
    Linuxdebianwebkit2gtkbullseye
    macOSapplemacos—
    Mobileappleiphone_os—
    Otherfedoraprojectfedora37
    Otherfedoraprojectfedora38
    Otherfedoraprojectfedora39
    Otherappleipados—

    Weakness classes (CWE)

    • CWE-754Improper Check for Unusual or Exceptional Conditions

      Class

      The product does not check or incorrectly checks for unusual or exceptional conditions that are not expected to occur frequently during day to day operation of the product.

      Entry at MITRE CWE-754

    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
    Apple (CVE.org)CVE.org (MITRE) (opens in a new tab)actively exploited
    CSA/SingCERTActive Exploitation of Zero-Day Vulnerabilities in Apple Products (opens in a new tab)CSA/SingCERTactively exploited
    PoC-in-GitHub (nomi-sec)CVE-2023-41993 (opens in a new tab)github.comPoC (publicly reported)reported, not verified

    References & sources

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