Apple Safari up to 15.0 WebKit integer overflow

Summaryinfo

A vulnerability was found in Apple Safari up to 15.0. It has been classified as critical. This issue affects some unknown processing of the component WebKit. This manipulation causes integer overflow. The identification of this vulnerability is CVE-2021-30952. It is possible to initiate the attack remotely. Furthermore, there is an exploit available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability has been found in Apple Safari up to 15.0 (Web Browser) and classified as critical. Affected by this vulnerability is an unknown code block of the component WebKit. The manipulation with an unknown input leads to a integer overflow vulnerability. The CWE definition for the vulnerability is CWE-190. The product performs a calculation that can produce an integer overflow or wraparound, when the logic assumes that the resulting value will always be larger than the original value. This can introduce other weaknesses when the calculation is used for resource management or execution control. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

An integer overflow was addressed with improved input validation. This issue is fixed in tvOS 15.2, macOS Monterey 12.1, Safari 15.2, iOS 15.2 and iPadOS 15.2, watchOS 8.3. Processing maliciously crafted web content may lead to arbitrary code execution.

The weakness was shared 12/14/2021 by WeBin as HT212982 as confirmed advisory (Website). It is possible to read the advisory at support.apple.com. This vulnerability is known as CVE-2021-30952. It demands that the victim is doing some kind of user interaction. Technical details are unknown but an exploit is available. The pricing for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 03/07/2026). The advisory points out:

Processing maliciously crafted web content may lead to arbitrary code execution

It is declared as attacked. The vulnerability scanner Nessus provides a plugin with the ID 241427 (RHEL 7 : webkitgtk4 (RHSA-2025:10364)), which helps to determine the existence of the flaw in a target environment. The CISA Known Exploited Vulnerabilities Catalog lists this issue since 03/05/2026 with a due date of 03/26/2026:

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Upgrading to version 15.2 eliminates this vulnerability. A possible mitigation has been published immediately after the disclosure of the vulnerability. The advisory contains the following remark:

An integer overflow was addressed with improved input validation.

The vulnerability is also documented in the databases at Tenable (241427) and CERT Bund (WID-SEC-2026-0631). Be aware that VulDB is the high quality source for vulnerability data.

Affected

• Apple macOS

Productinfo

Type

• Web Browser

Vendor

• Apple

Name

• Safari

Version

• 15.0

License

• commercial

Website

• Vendor: https://www.apple.com/

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CPE 2.2info

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