Medium

WebKit array allocation sinking crash in Safari/WebKitGTK/WPE WebKit

IdentifiersCVE-2025-43421CWE-400

CVE-2025-43421 is a WebKit vulnerability affecting Safari and related Apple platforms, as well as WebKitGTK and WPE WebKit before 2.50.3. According to the provided advisories, multiple issues were addressed by disabling array allocation sinking. Processing maliciously crafted web content can trigger an unexpected process crash. The issue was credited to Nan Wang (@eternalsakura13). Fixed versions cited in the provided content include Safari 26.1, iOS 26.1, iPadOS 26.1, macOS Tahoe 26.1, visionOS 26.1, and WebKitGTK/WPE WebKit 2.50.3.

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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 can cause denial of service by crashing the affected browser or WebKit-based content-processing process when a target renders attacker-controlled web content. The provided content does not establish code execution or data disclosure for this CVE; the documented impact is limited to unexpected process crash.

Mitigation

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

If patching is not immediately possible, reduce exposure to untrusted web content. For WebKitGTK-based environments, restrict or avoid use of applications that render attacker-supplied web pages, and consider limiting access to untrusted sites until updates are deployed. No vendor-specific workaround beyond the fix is provided in the supplied content.

Remediation

Patch, then assume compromise.

Apply the vendor fixes: update Safari to 26.1, iOS/iPadOS to 26.1, macOS Tahoe to 26.1, visionOS to 26.1, and update WebKitGTK or WPE WebKit to version 2.50.3 or later. Debian guidance in the provided content recommends upgrading webkit2gtk to 2.50.3-1~deb12u1 for bookworm or 2.50.3-1~deb13u1 for trixie, as appropriate.

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

AppleSafariapplication

AppleVisionosoperating_system

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

ACTIVITY FEED

Recent activity

5 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.

5 SOURCESView more in app

zdnet zero dayNews

Jan 24, 2026

About the security content of iOS 26.1 and iPadOS 26.1 - Apple Support

Cross-origin image data exfiltration due to cache handling weaknesses.

apple supportNews

Dec 12, 2025

About the security content of Safari 26.1 - Apple Support (MT)

A web content processing vulnerability tied to array allocation sinking behavior that may cause an unexpected process crash on macOS Sonoma and macOS Sequoia.

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 activity2