CriticalCVE-2025-24201

    Apple Multiple Products WebKit Out-of-Bounds Write Vulnerability (CVE-2025-24201)

    Published In CISA KEV since Sources: Debian, Debian LTS, pwn.watch, CVE.org, Msrc Update Guide, Red Hat

    What is affected, what to do

    An out-of-bounds write issue was addressed with improved checks to prevent unauthorized actions. This issue is fixed in Safari 18.3.1, iOS 15.8.4 and iPadOS 15.8.4, iOS 16.7.11 and iPadOS 16.7.11, iOS 18.3.2 and iPadOS 18.3.2, iPadOS 17.7.6, macOS Sequoia 15.3.2, visionOS 2.3.2, watchOS 11.4.

    The vulnerability is being actively exploited; treat it as a priority. Update Apple Safari to version 18.3.1, Apple iOS and iPadOS to version 15.8.4, Apple iOS and iPadOS to version 16.7.11. Immediate actions, mitigation and detection rules are in the runbook below.

    Affected
    • Apple Safari lt *..18.3.1
    • Apple iOS and iPadOS lt *..15.8.4
    • Apple iOS and iPadOS lt *..16.7.11
    • Apple iOS and iPadOS lt *..18.3.2
    • Apple iPadOS lt *..17.7.6
    • Apple macOS lt *..15.3.2
    • Apple visionOS lt *..2.3.2
    • Apple watchOS lt *..11.4
    Fixed in
    • Apple Safari 18.3.1
    • Apple iOS and iPadOS 15.8.4
    • Apple iOS and iPadOS 16.7.11
    • Apple iOS and iPadOS 18.3.2
    • Apple iPadOS 17.7.6
    • Apple macOS 15.3.2
    • Apple visionOS 2.3.2
    • Apple watchOS 11.4

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

    Metrics

    10.0

    Priority

    XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.

    Source: NVD, CVSS v3

    10.0

    CVSS v3

    Severity Critical on the scale from 0 to 10.

    Source: Debian, Debian LTS, pwn.watch, CVE.org, Msrc Update Guide, Red Hat

    3.9 %

    EPSS score

    Moderate — model estimates 1-10% exploitation likelihood.

    Source: FIRST EPSS, percentile 90.1

    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
    223.08 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), Apple (CVE.org) 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
    10.0 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
    10.0
    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
    3.9 %
    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
    90.1
    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

    Response and mitigation

    Why act now?

    Prioritisation rationale

    The flaw is network-reachable without authentication, needs nothing more than rendering crafted web content, and lets an attacker escape the WebContent sandbox with impact beyond that security boundary — a textbook stage in commercial-spyware exploit chains. Apple confirms extremely sophisticated, targeted attacks against specific individuals; there is no known ransomware use, and while exploitation likelihood is clearly above average, it is not in the tier of mass-exploited CVEs. For NIS2/KRITIS organisations, rate this "high" across the whole Apple fleet and "critical" for executives, administrators and anyone with access to sensitive information, targeting near-complete patch coverage within 72 hours.

    1. Runbook step 1

      Immediate response (0-24 h)

      • Force the patch via MDM: iOS/iPadOS 18.3.2, iPadOS 17.7.6, iOS/iPadOS 16.7.11, iOS/iPadOS 15.8.4, macOS Sequoia 15.3.2, Safari 18.3.1 (for older supported macOS releases), visionOS 2.3.2 and watchOS 11.4. Set the minimum OS version as a compliance rule in Intune, Jamf or Kandji and push an enforced update with a deadline (e.g. Declarative Device Management softwareupdate.enforcement.specific).
      • Block non-compliant devices: use Conditional Access to cut devices below the fixed versions off from mail, VPN, Microsoft 365 and internal web apps until they update.
      • Prioritise high-risk users: patch and personally brief executives, board members, legal, crisis team, staff with government contact and administrators first. Enable Lockdown Mode for this group.
      • Inventory non-Apple WebKit consumers: find Linux hosts and appliances running WebKitGTK or WPE WebKit (kiosks, HMI panels, embedded browsers, headless HTML-to-PDF renderers). Patch available from the respective vendor or distribution — check the vendor advisory for the fixed version.
      • Retire stranded devices: devices that cannot receive any of the listed versions are unsupported; remove their access to corporate resources and schedule replacement.

    2. Runbook step 2

      Mitigation layers

      • Endpoint configuration: Lockdown Mode disables JIT and many complex web features in WebKit, sharply reducing the attack surface for WebKit memory-corruption bugs. On macOS, enforce automatic Rapid Security Responses / background security updates via configuration profile.
      • Network / web proxy: enforce a secure web gateway or DNS filter on mobile devices (MDM-deployed VPN or DNS profile); block newly registered and uncategorised domains, especially short-link redirectors arriving via SMS and messengers, a common delivery path for targeted exploit chains.
      • Segmentation: kiosk and HMI systems running WebKit-based browsers in OT or building networks should reach only allow-listed internal destinations (allow-list proxy, default-deny egress); no open internet access.
      • Server-side renderers: services that render untrusted HTML with WebKit (preview generators, PDF converters) belong in containers with seccomp/AppArmor profiles, no network egress and an unprivileged user, since a sandbox escape otherwise reaches the host.
      • IAM / least privilege: keep no long-lived privileged credentials on high-risk users' mobile devices; allow admin access only from separate hardened workstations with phishing-resistant MFA (FIDO2).

    3. Runbook step 3

      Detection rules

      • MDM/EDR inventory as primary source: continuously list vulnerable devices, e.g. in Defender XDR: DeviceInfo | where OSPlatform in ("iOS","macOS") | summarize arg_max(Timestamp,*) by DeviceId | project DeviceName, OSPlatform, OSVersion, LoggedOnUsers and compare against the fixed versions.
      • macOS process ancestry (EDR): children of com.apple.WebKit.WebContent or com.apple.WebKit.Networking other than known XPC helpers are highly suspicious. Sigma shape: ParentImage|endswith: 'com.apple.WebKit.WebContent' AND Image|endswith: ['/sh','/bash','/zsh','/osascript','/curl','/python3'].
      • Crashes and sandbox denials: clusters of .ips crash reports for com.apple.WebKit.WebContent and Sandbox: ... deny entries in the unified log (log show --predicate 'sender == "Sandbox" AND process CONTAINS "WebContent"') on exposed users' devices warrant investigation; failed exploit attempts often leave these traces.
      • iOS compromise triage: collect a sysdiagnose or encrypted backup and run the Mobile Verification Toolkit (MVT) against current public IOC sets. Treat any Apple Threat Notification received by staff as a security incident.
      • Proxy / web logs: alert on outdated Safari user agents hitting internal applications; correlate one-off mobile visits to newly registered domains shortly after SMS/iMessage receipt in Zeek dns.log or proxy logs.

    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

    An out-of-bounds write issue was addressed with improved checks to prevent unauthorized actions. This issue is fixed in Safari 18.3.1, iOS 15.8.4 and iPadOS 15.8.4, iOS 16.7.11 and iPadOS 16.7.11, iOS 18.3.2 and iPadOS 18.3.2, iPadOS 17.7.6, macOS Sequoia 15.3.2, visionOS 2.3.2, watchOS 11.4. Maliciously crafted web content may be able to break out of Web Content sandbox. This is a supplementary fix for an attack that was blocked in iOS 17.2. (Apple is aware of a report that this issue may have been exploited in an extremely sophisticated attack against specific targeted individuals on versions of iOS before iOS 17.2.).

    Source: Debian Security Advisories, Debian LTS Advisories, pwn.watch, NVD (NIST), Microsoft Security Update Guide, 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
    AppleiOS and iPadOS
    • < 15.8.4
    • < 18.3.2
    • < 16.7.11
    • 15.8.4
    • 18.3.2
    • 16.7.11
    AppleiPadOS
    • < 17.7.6
    • 17.7.6
    ApplemacOS
    • < 15.3.2
    • 15.3.2
    AppleSafari
    • < 18.3.1
    • 18.3.1
    ApplevisionOS
    • < 2.3.2
    • 2.3.2
    ApplewatchOS
    • < 11.4
    • 11.4
    applesafari
    • < 18.3.1
    • 18.3.1

    Vendors and products

    Affected operating systems

    Affected operating systems
    Linuxdebianchromiumbookworm
    Linuxdebiandebian_linux11.0
    Linuxdebianwebkit2gtkbookworm
    Linuxdebianwebkit2gtkbullseye
    macOSapplemacos—
    Mobileappleiphone_os—
    Otherappleipados—
    Otherapplevisionos—
    Otherapplewatchos—

    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
    GitHubJGoyd/Glass-Cage-iOS18-CVE-2025-24085-CVE-2025-24201 (opens in a new tab)github.comPoC (publicly reported)reported, not verified—

    References & sources

    • support.apple.comApple advisory: Apple Multiple ProductsRelease notes, Vendor advisory, pwn-watch
    • support.apple.comApple advisory: Apple Multiple ProductsRelease notes, Vendor advisory, pwn-watch
    • support.apple.comApple advisory: Apple Multiple ProductsRelease notes, Vendor advisory, pwn-watch
    • support.apple.comApple advisory: Apple Multiple ProductsRelease notes, Vendor advisory, pwn-watch
    • support.apple.comen-us/122345Release notes, Vendor advisory
    • support.apple.comen-us/122346Release notes, Vendor advisory
    • support.apple.comen-us/122372Release notes, Vendor advisory
    • support.apple.comen-us/122376Release notes, Vendor advisory
    • cisa.govknown-exploited-vulnerabilities-catalog?field_cve=CVE-2025-24201government-resource, US government resource
    • seclists.orgfulldisclosure/2025/Mar/2Mailing list, Third-party advisory
    • seclists.orgfulldisclosure/2025/Mar/3Mailing list, Third-party advisory
    • seclists.orgfulldisclosure/2025/Mar/4Mailing list, Third-party advisory
    • seclists.orgfulldisclosure/2025/Mar/5Mailing list, Third-party advisory
    • seclists.orgfulldisclosure/2025/Apr/16Mailing list, Third-party advisory
    • seclists.orgfulldisclosure/2025/Oct/31Mailing list, Third-party advisory
    • seclists.orgfulldisclosure/2025/Oct/1Mailing list, Third-party advisory
    • lists.debian.orgdebian-lts-announce/2025/06/msg00016.htmlMailing list
    • seclists.orgfulldisclosure/2025/Jun/19Mailing list, Third-party advisory
    • seclists.orgfulldisclosure/2025/Apr/7Mailing list, Third-party advisory
    • github.comJGoyd/Glass-Cage-iOS18-CVE-2025-24085-CVE-2025-24201Third-party advisory
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