Universal XSS in Apple Safari and Apple operating systems WebKit
CVE-2024-40857 is a web content processing vulnerability in Apple Safari 18, visionOS 2, watchOS 11, macOS Sequoia 15, iOS 18, iPadOS 18, and tvOS 18. Apple states that processing maliciously crafted web content may lead to universal cross-site scripting (UXSS). The issue was remediated through improved state management. Based on the advisory language, the flaw affects browser/web content security boundary handling rather than a memory-safety condition, allowing attacker-controlled script execution in an unintended web security context.
Are you exposed to this one?
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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
3 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
A cross-origin issue involving iframe elements that could enable cross-origin data exfiltration; fixed by improved tracking of security origins.
Cross-origin issue involving iframe elements; fixed by improved tracking of security origins.
A web content processing issue leading to universal cross-site scripting (UXSS) on Apple TV.
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.