Apple watchOS up to 8.1.1 WebKit integer overflow

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7.5	$0-$5k	0.00

Summaryinfo

A vulnerability, which was classified as critical, has been found in Apple watchOS up to 8.1.1. The impacted element is an unknown function of the component WebKit. The manipulation leads to integer overflow. This vulnerability is referenced as CVE-2021-30952. Remote exploitation of the attack is possible. Furthermore, an exploit is available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as critical, has been found in Apple watchOS up to 8.1.1 (Smartwatch Operating System). This issue affects an unknown functionality of the component WebKit. The manipulation with an unknown input leads to a integer overflow vulnerability. Using CWE to declare the problem leads to 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. Impacted is 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 published 12/13/2021 by WeBin as HT212975 as confirmed advisory (Website). The advisory is shared at support.apple.com. The identification of this vulnerability is 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 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 8.3 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). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Affected

Apple macOS

Productinfo

Type

Smartwatch Operating System

Vendor

Apple

Name

watchOS

Version

License

commercial

Website

Vendor: https://www.apple.com/

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.6
VulDB Meta Temp Score: 7.5

VulDB Base Score: 6.3
VulDB Temp Score: 6.0
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 7.8
NVD Vector: 🔍

ADP CISA Base Score: 8.8
ADP CISA Vector: 🔍

CVSSv2info

AV	AC	Au	C	I	A
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Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

NVD Base Score: 🔍

Exploitinginfo

Class: Integer overflow
CWE: CWE-190 / CWE-189
CAPEC: 🔍
ATT&CK: 🔍

Physical: Partially
Local: Yes
Remote: Yes

Availability: 🔍
Status: Attacked

EPSS Score: 🔍
EPSS Percentile: 🔍

KEV Added: 🔍
KEV Due: 🔍
KEV Remediation: 🔍
KEV Ransomware: 🔍
KEV Notice: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Nessus ID: 241427
Nessus Name: RHEL 7 : webkitgtk4 (RHSA-2025:10364)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

Reaction Time: 🔍
0-Day Time: 🔍
Exposure Time: 🔍

Upgrade: watchOS 8.3

Timelineinfo

04/13/2021 🔍
12/13/2021 +244 days 🔍
12/13/2021 +0 days 🔍
12/17/2021 +4 days 🔍
03/07/2026 +1541 days 🔍

Sourcesinfo

Vendor: apple.com

Advisory: HT212975
Researcher: WeBin
Status: Confirmed

CVE: CVE-2021-30952 (🔍)
GCVE (CVE): GCVE-0-2021-30952
GCVE (VulDB): GCVE-100-188525
CERT Bund: WID-SEC-2026-0631 - Apple macOS: Mehrere Schwachstellen

scip Labs: https://www.scip.ch/en/?labs.20161013

Entryinfo

Created: 12/17/2021 16:06
Updated: 03/07/2026 12:18
Changes: 12/17/2021 16:06 (19), 12/17/2021 16:09 (27), 12/23/2021 07:43 (1), 07/11/2025 01:36 (16), 03/05/2026 21:25 (29), 03/05/2026 23:01 (13), 03/07/2026 12:18 (7)
Complete: 🔍
Cache ID: 216::103

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