Medium

WebKit sandbox escape via restricted web content processing

IdentifiersCVE-2026-28859CWE-119

CVE-2026-28859 is a WebKit vulnerability affecting Apple platforms and WebKitGTK/WPE WebKit before 2.52.1. Apple describes the issue as one where a malicious website may be able to process restricted web content outside the sandbox. The flaw was addressed with improved memory handling, indicating a memory-safety issue in WebKit that could allow web content to cross intended sandbox boundaries during content processing. Publicly available advisory text does not identify the specific vulnerable function, but Apple and WebKitGTK/WPE associate the issue with WebKit Bugzilla 308248.

For your environment

Are you exposed to this one?

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation could allow attacker-controlled web content from a malicious website to be processed outside the intended WebKit sandbox restrictions. This represents a sandbox bypass / sandbox escape condition that weakens browser isolation and could expose the affected process or system to additional attack surface beyond normal web-content confinement.

Mitigation

If you can’t patch tonight, do this now.

Until patches can be applied, reduce exposure by limiting access to untrusted websites and web content, especially on systems embedding vulnerable WebKit components. Where operationally feasible, disable or restrict use of affected WebKit-based browsing contexts and keep WebKitGTK/WPE deployments updated to current stable releases. No vendor-specific workaround beyond updating is provided in the supplied content.

Remediation

Patch, then assume compromise.

Apply the vendor fixes: Safari 26.4; iOS 26.4 and iPadOS 26.4; macOS Tahoe 26.4; tvOS 26.4; visionOS 26.4; watchOS 26.4. For WebKitGTK and WPE WebKit, upgrade to version 2.52.1 or later. Apple states the issue was fixed through improved memory handling.

PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType

AppleIpadosoperating_system

AppleIphone Osoperating_system

AppleMacosoperating_system

AppleSafariapplication

AppleTvosoperating_system

AppleVisionosoperating_system

AppleWatchosoperating_system

Rocky LinuxRocky Linuxoperating_system

WebkitgtkWebkit2gtk3application

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

13 sources tracked across advisories and community write-ups. News coverage will land here when it surfaces.

13 SOURCESView more in app

No news coverage yet. Advisories and community discussion only.

What this page doesn’t show

The version that knows your environment.

This page is what’s public. Mallory adds the parts that aren’t: which of your assets are affected, which adversaries are exploiting it right now, which detections to deploy, and what to do tonight.

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Exposure mapping

Query your assets running an affected version, and investigate the blast radius.

Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity9