WebKit cross-origin script message handler access
CVE-2026-28861 is a WebKit logic flaw caused by improper state management that allows a malicious website to access script message handlers intended for other origins. Apple describes the issue as a logic issue fixed with improved state management, and WebKitGTK/WPE WebKit report the same impact for versions before 2.52.1. The vulnerability affects WebKit as shipped in Safari 26.4, iOS 18.7.7, iPadOS 18.7.7, iOS 26.4, iPadOS 26.4, macOS Tahoe 26.4, visionOS 26.4, and WebKitGTK/WPE WebKit before 2.52.1. The issue breaks expected origin isolation around script message handlers exposed to web content.
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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.
Mitigation
If you can’t patch tonight, do this now.
Remediation
Patch, then assume compromise.
Exploits
No public exploits tracked yet. Mallory keeps watching.
No public exploit code observed for this vulnerability.
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.
Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
Recent activity
9 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
A WebKit browser-engine vulnerability involved in malicious web content handling as part of a set of browser security flaws.
A logic issue that may allow a malicious website to access script message handlers intended for other origins.
The version that knows your environment.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.