Apple Safari up to 15.0 WebKit out-of-bounds

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
6.0	$0-$5k	0.00

Summaryinfo

A vulnerability was found in Apple Safari up to 15.0. It has been rated as critical. The affected element is an unknown function of the component WebKit. Performing a manipulation results in out-of-bounds. This vulnerability is identified as CVE-2021-30953. The attack can be initiated remotely. There is not any exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in Apple Safari up to 15.0 (Web Browser). It has been classified as critical. This affects an unknown function of the component WebKit. The manipulation with an unknown input leads to a out-of-bounds vulnerability. CWE is classifying the issue as CWE-125. The product reads data past the end, or before the beginning, of the intended buffer. This is going to have an impact on confidentiality, integrity, and availability.

The weakness was released 12/14/2021 by VRIJ as HT212982 as confirmed advisory (Website). The advisory is shared at support.apple.com. This vulnerability is uniquely identified as CVE-2021-30953. It demands that the victim is doing some kind of user interaction. Neither technical details nor an exploit are publicly available. The advisory points out:

Processing maliciously crafted web content may lead to arbitrary code execution

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 out-of-bounds read was addressed with improved bounds checking.

The vulnerability is also documented in the vulnerability database at CERT Bund (WID-SEC-2026-0631). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Affected

Apple macOS

Productinfo

Type

Web Browser

Vendor

Apple

Name

Safari

Version

15.0

License

commercial

Website

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

CPE 2.3info

🔍

CPE 2.2info

🔍

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.3
VulDB Meta Temp Score: 6.0

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

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

Exploitinginfo

Class: Out-of-bounds
CWE: CWE-125 / CWE-119
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

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

Upgrade: Safari 15.2

Timelineinfo

04/13/2021 🔍
12/14/2021 +245 days 🔍
12/14/2021 +0 days 🔍
12/17/2021 +3 days 🔍
03/07/2026 +1541 days 🔍

Sourcesinfo

Vendor: apple.com

Advisory: HT212982
Researcher: VRIJ
Status: Confirmed

CVE: CVE-2021-30953 (🔍)
GCVE (CVE): GCVE-0-2021-30953
GCVE (VulDB): GCVE-100-188601
CERT Bund: WID-SEC-2026-0631 - Apple macOS: Mehrere Schwachstellen

Entryinfo

Created: 12/17/2021 16:59
Updated: 03/07/2026 14:22
Changes: 12/17/2021 16:59 (19), 12/17/2021 17:02 (27), 12/23/2021 13:15 (1), 03/07/2026 14:22 (21)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.