CriticalCVE-2022-22620

    Apple iOS, iPadOS, and macOS Webkit Use-After-Free Vulnerability (CVE-2022-22620)

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

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    What is affected, what to do

    A Use-After-Free vulnerability in Apple's WebKit for iOS, iPadOS, and macOS allows remote code execution by processing malicious web content. This affects HTML parsers using WebKit, including Apple Safari and some non-Apple products. The vulnerability is actively exploited in ransomware campaigns since 2022. Affected products include Safari 15.3, iPadOS 15.3.1, iOS 15.3.1, and macOS 12.0.0 to 12.2.1. Immediate patching to macOS Monterey 12.2.1, iOS 15.3.1, iPadOS 15.3.1, or Safari 15.3 is recommended.

    The vulnerability is being actively exploited; treat it as a priority. Update Apple Safari (v and ) to version 15.3, Apple macOS to version 12.2, Apple macOS to version 15.3. Immediate actions, mitigation and detection rules are in the runbook below.

    Affected
    • Apple Safari (v and ) lt *..15.3
    • Apple macOS lt *..12.2
    • Apple macOS lt *..15.3
    Fixed in
    • Apple Safari (v and ) 15.3
    • Apple macOS 12.2
    • Apple macOS 15.3

    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, CVE.org, Red Hat

    16.3 %

    EPSS score

    Elevated — model estimates 10-50% exploitation likelihood.

    Source: FIRST EPSS, percentile 97.0

    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
    219.78 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
    16.3 %
    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
    97.0
    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-416

    Response and mitigation

    Why act now?

    Prioritisation rationale

    This flaw is network-reachable without authentication and needs only a user to load crafted web content — a messenger link, a compromised site or a malvertising slot is enough — yielding code execution in the renderer with full confidentiality, integrity and availability impact. Apple shipped it as an out-of-band fix; WebKit bugs of this class are typically used as the initial stage of exploit chains against hand-picked individuals (executives, journalists, administrators), and CISA records no known ransomware use. Exploitation likelihood is high relative to the overall CVE population. For organisations with managed Apple fleets this is now mainly a hygiene signal: treat any remaining unpatched device as high priority, and as critical for high-profile users or WebKit-based display systems in critical-infrastructure environments.

    1. Runbook step 1

      Immediate response (0-24 h)

      • Inventory exposed devices: Use your MDM (Jamf, Intune, Kandji, Workspace ONE) to find every Apple endpoint below macOS Monterey 12.2.1, iOS 15.3.1 and iPadOS 15.3.1, plus Safari installs below 15.3 (build 16612.4.9.1.8 on Big Sur, 15612.4.9.1.8 on Catalina). In Defender for Endpoint: DeviceTvmSoftwareVulnerabilities | where CveId == "CVE-2022-22620" | summarize by DeviceName, OSPlatform, SoftwareVersion.
      • Push the vendor fix: Force macOS Monterey 12.2.1, iOS/iPadOS 15.3.1, or Safari 15.3 on Big Sur and Catalina via MDM update commands with a deferral of no more than 24 hours. The fix has shipped since February 2022, so any device still unpatched today is a patch-management outlier and warrants individual follow-up.
      • Don't trust alternative browsers on iOS: Chrome, Firefox, Edge and in-app web views on iOS/iPadOS all render through WebKit. Switching browsers is not a mitigation; only the OS update is.
      • Quarantine devices that can't update: Block non-compliant devices from corporate resources (M365, VPN, internal web apps) via Conditional Access/compliance policy until they reach the minimum version.
      • Hunt for non-Apple WebKit: Identify Linux systems running WebKitGTK or WPE WebKit (kiosks, HMI panels, embedded displays, Epiphany). Patch available from the vendor or distribution — look up the fixed version in the respective security advisory.

    2. Runbook step 2

      Mitigation layers

      • Network/web proxy: Block "Newly Registered Domains", "Uncategorized" and known malvertising categories at the secure web gateway; enable TLS inspection for managed Apple devices where legally permissible so exploit-kit content can be inspected.
      • DNS layer: Enforce protective DNS on mobile devices (e.g. via the com.apple.dnsSettings.managed MDM payload) so malicious domains are blocked off-network too.
      • Endpoint hardening for high-risk users: Evaluate Lockdown Mode (iOS 16/macOS Ventura and later) for executives, admins and other exposed roles — it disables JIT and complex web features, sharply shrinking the WebKit attack surface.
      • Configuration/compliance: Set the MDM minimum-OS compliance rule to 15.3.1 (iOS/iPadOS) and 12.2.1 (macOS), tie non-compliance automatically to Conditional Access, and enforce automatic updates (AutomaticallyInstallMacOSUpdates, CriticalUpdateInstall) via profile.
      • Embedded WebKit systems: Restrict WebKitGTK-based kiosk/HMI devices to an allowlist proxy (required internal URLs only) and deny outbound internet access from their VLAN.

    3. Runbook step 3

      Detection rules

      • EDR process ancestry (macOS): Unexpected children of the WebKit renderer. KQL: DeviceProcessEvents | where InitiatingProcessFileName startswith "com.apple.WebKit.WebContent" | where FileName in~ ("sh","bash","zsh","osascript","curl","python3","perl"). Any hit is high-fidelity — the sandboxed renderer never legitimately spawns shells.
      • Crash reports as early warning: Correlate clusters of com.apple.WebKit.WebContent crash reports (/Library/Logs/DiagnosticReports/*.ips, ~/Library/Logs/DiagnosticReports/) with EXC_BAD_ACCESS on unpatched devices via EDR or MDM log collection — failed use-after-free attempts often crash the renderer.
      • Linux/WebKitGTK (auditd): -a always,exit -F arch=b64 -S execve -k webkit_exec, alerting when the parent is WebKitWebProcess (Sigma: ParentImage|endswith: '/WebKitWebProcess' with Image|endswith: ['/sh','/bash','/curl','/wget']).
      • Network telemetry (proxy/Zeek): A visit to a rare or newly registered domain followed shortly by connections from the same device to further unknown hosts (second-stage pull), particularly Mach-O payloads in HTTP responses (Content-Type: application/octet-stream, magic bytes CFFAEDFE).
      • Compliance drift: Run a daily MDM/SIEM query for devices below the minimum version; a device that keeps reporting an old build after a forced update may indicate tampering or loss of management.

    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

    A use after free issue was addressed with improved memory management. This issue is fixed in macOS Monterey 12.2.1, iOS 15.3.1 and iPadOS 15.3.1, Safari 15.3 (v. 16612.4.9.1.8 and 15612.4.9.1.8). Processing maliciously crafted web content may lead to arbitrary code execution. Apple is aware of a report that this issue may have been actively exploited..

    Source: CSA/SingCERT, Debian Security Advisories, NVD (NIST), 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
    • < 15.3
    • < 12.2
    • 15.3
    • 12.2
    AppleSafari (v and )
    • < 15.3
    • 15.3
    applesafari
    • < 15.3
    • 15.3

    Vendors and products

    Affected operating systems

    Affected operating systems
    Linuxdebianwebkit2gtkbullseye
    Linuxdebianwebkit2gtkbuster
    Linuxdebianwpewebkitbullseye
    macOSapplemacos—
    Mobileappleiphone_os—
    Otherappleipados—

    Weakness classes (CWE)

    • CWE-416Use After Free

      Variant

      The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.

      Entry at MITRE CWE-416

    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/SingCERTZero-Day Vulnerability in Apple iPhone, iPad, and Mac (opens in a new tab)CSA/SingCERTactively exploited

    References & sources

    • support.apple.comen-us/HT213091x_refsource_MISC, Release notes, Vendor advisory
    • support.apple.comen-us/HT213092x_refsource_MISC, Release notes, Vendor advisory
    • support.apple.comen-us/HT213093x_refsource_MISC, Release notes, Vendor advisory
    • security.gentoo.orgGLSA-202208-39Vendor advisory, x_refsource_GENTOO, Third-party advisory
    • cisa.govknown-exploited-vulnerabilities-catalog?field_cve=CVE-2022-22620government-resource, Third-party advisory, US government resource
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