VDB-169061 · CVE-2021-1776 · HT212147

Apple macOS up to 11.1 CoreGraphics out-of-bounds write

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.
5.7	$0-$5k	0.00

Summaryinfo

A vulnerability marked as critical has been reported in Apple macOS up to 11.1. This affects an unknown part of the component CoreGraphics. The manipulation leads to out-of-bounds write. This vulnerability is documented as CVE-2021-1776. The attack can be initiated remotely. Additionally, an exploit exists. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in Apple macOS up to 11.1 (Operating System) and classified as critical. This issue affects an unknown code of the component CoreGraphics. The manipulation with an unknown input leads to a out-of-bounds write vulnerability. Using CWE to declare the problem leads to CWE-787. The product writes data past the end, or before the beginning, of the intended buffer. Impacted is confidentiality, integrity, and availability.

The weakness was released 02/01/2021 by Ivan Fratric as HT212147 as confirmed advisory (Website). The advisory is shared at support.apple.com. The identification of this vulnerability is CVE-2021-1776. It demands that the victim is doing some kind of user interaction. Technical details are unknown but a public exploit is available. The advisory points out:

Processing a maliciously crafted font file may lead to arbitrary code execution

The exploit is available at packetstormsecurity.com. It is declared as proof-of-concept. We expect the 0-day to have been worth approximately $5k-$25k.

Upgrading to version 11.2 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 write issue was addressed with improved bounds checking.

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Type

Operating System

Vendor

Apple

Name

macOS

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: 6.3
VulDB Meta Temp Score: 5.7

VulDB Base Score: 6.3
VulDB Temp Score: 5.7
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 write
CWE: CWE-787 / CWE-119
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Access: Public
Status: Proof-of-Concept
Download: 🔍

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: macOS 11.2

Timelineinfo

12/08/2020 🔍
02/01/2021 +55 days 🔍
02/01/2021 +0 days 🔍
02/03/2021 +2 days 🔍
05/04/2025 +1551 days 🔍

Sourcesinfo

Vendor: apple.com

Advisory: HT212147
Researcher: Ivan Fratric
Status: Confirmed

CVE: CVE-2021-1776 (🔍)
GCVE (CVE): GCVE-0-2021-1776
GCVE (VulDB): GCVE-100-169061
scip Labs: https://www.scip.ch/en/?labs.20180712

Entryinfo

Created: 02/03/2021 13:30
Updated: 05/04/2025 07:03
Changes: 02/03/2021 13:30 (19), 02/03/2021 13:33 (10), 02/03/2021 13:34 (18), 02/22/2021 16:45 (4), 06/29/2024 14:01 (23), 05/04/2025 07:03 (3)
Complete: 🔍
Cache ID: 216::103