Skip to main content
Meet us at Black Hat USA 2026— Las Vegas, August 1–6Book a Meeting
Mallory
Unrated

Cross-origin data exfiltration in WebKit

IdentifiersCVE-2026-43708CWE-20

CVE-2026-43708 is a WebKit vulnerability affecting Safari 26.5.2 prior versions, iOS 26.5.2 prior versions, iPadOS 26.5.2 prior versions, and macOS Tahoe 26.5.2 prior versions. Apple states that a malicious website may exfiltrate data cross-origin and that the issue was addressed with improved input validation. Based on the available information, the flaw is a cross-origin validation/input handling weakness in WebKit that permits unauthorized cross-origin data access or exfiltration by attacker-controlled web content.

Share:
For your environment

Are you exposed to this one?

Mallory correlates every CVE against your assets, your vendors, and active adversary campaigns. Know which vulnerabilities matter for you, not just which ones are loud.

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 allows a malicious website to exfiltrate data across origin boundaries. This can result in unauthorized disclosure of sensitive information accessible within the browser context, undermining the browser same-origin security model and potentially exposing user data from other sites or origins.

Mitigation

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

Apply the vendor patches. Until updates can be deployed, reduce exposure by limiting use of untrusted websites and untrusted web content in affected Safari/WebKit-based contexts. Because exploitation requires visiting a malicious website, restricting browsing to trusted sites may reduce risk, but no complete mitigation short of patching is provided in the available information.

Remediation

Patch, then assume compromise.

Upgrade affected systems to the fixed releases provided by Apple: Safari 26.5.2, iOS 26.5.2, iPadOS 26.5.2, and macOS Tahoe 26.5.2. Apple indicates the issue was fixed through improved input validation in WebKit.
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

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

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.
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 activity

Community discussion across Reddit, Mastodon, and other social sources.