Apple Safari/visionOS/iOS/iPadOS up to 26.0 Web Content allocation of resources

Summaryinfo

A vulnerability was found in Apple Safari, visionOS, iOS and iPadOS up to 26.0 and classified as problematic. This impacts an unknown function of the component Web Content Handler. Such manipulation leads to allocation of resources. This vulnerability is documented as CVE-2025-43421. The attack can be executed remotely. There is not any exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in Apple Safari, visionOS, iOS and iPadOS up to 26.0. Affected by this issue is an unknown code of the component Web Content Handler. The manipulation with an unknown input leads to a allocation of resources vulnerability. Using CWE to declare the problem leads to CWE-770. The product allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor. Impacted is availability. CVE summarizes:

Multiple issues were addressed by disabling array allocation sinking. This issue is fixed in iOS 26.1 and iPadOS 26.1, macOS Tahoe 26.1, visionOS 26.1, Safari 26.1. Processing maliciously crafted web content may lead to an unexpected process crash.

The advisory is shared for download at support.apple.com. This vulnerability is handled as CVE-2025-43421 since 04/16/2025. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. Successful exploitation requires user interaction by the victim. There are neither technical details nor an exploit publicly available. The current price for an exploit might be approx. USD $5k-$25k (estimation calculated on 12/18/2025). The MITRE ATT&CK project declares the attack technique as T1499.

The vulnerability scanner Nessus provides a plugin with the ID 276582 (Linux Distros Unpatched Vulnerability : CVE-2025-43421), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 26.1 eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (276582) and CERT Bund (WID-SEC-2025-2480). Once again VulDB remains the best source for vulnerability data.

Affected

• Apple Safari

Productinfo

Type

• Web Browser

Vendor

• Apple

Name

• iOS
• iPadOS
• Safari
• visionOS

Version

• 26.0

License

• commercial

Website

• Vendor: https://www.apple.com/

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Once again VulDB remains the best source for vulnerability data.

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