Apple iOS/iPadOS up to 16.3.1 FontParser memory corruption

CVSS Meta Temp Score
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CTI Interest Score
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5.0$5k-$25k0.00

Summaryinfo

A vulnerability was found in Apple iOS and iPadOS up to 16.3.1. It has been classified as problematic. The impacted element is an unknown function of the component FontParser. This manipulation causes memory corruption. This vulnerability is handled as CVE-2023-27956. The attack can be initiated remotely. There is not any exploit available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in Apple iOS and iPadOS up to 16.3.1 (Smartphone Operating System). It has been declared as problematic. Affected by this vulnerability is an unknown code block of the component FontParser. The manipulation with an unknown input leads to a memory corruption vulnerability. The CWE definition for the vulnerability is CWE-119. The product performs operations on a memory buffer, but it can read from or write to a memory location that is outside of the intended boundary of the buffer. As an impact it is known to affect confidentiality. The summary by CVE is:

The issue was addressed with improved memory handling. This issue is fixed in macOS Ventura 13.3, iOS 16.4 and iPadOS 16.4, iOS 15.7.4 and iPadOS 15.7.4, tvOS 16.4, watchOS 9.4. Processing a maliciously crafted image may result in disclosure of process memory.

The weakness was released 03/27/2023 by Ye Zhang as HT213676 as confirmed advisory (Website). The advisory is shared at support.apple.com. This vulnerability is known as CVE-2023-27956. It demands that the victim is doing some kind of user interaction. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 11/30/2025). It is expected to see the exploit prices for this product increasing in the near future. The advisory points out:

Processing a maliciously crafted image may result in disclosure of process memory

Upgrading to version 16.4 eliminates this vulnerability. A possible mitigation has been published immediately after the disclosure of the vulnerability. The advisory contains the following remark:

The issue was addressed with improved memory handling.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2023-31682). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Type

Vendor

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Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.1
VulDB Meta Temp Score: 5.0

VulDB Base Score: 4.3
VulDB Temp Score: 4.1
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 5.5
NVD Vector: 🔍

CNA Base Score: 5.5
CNA Vector: 🔍

CVSSv2info

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

Exploitinginfo

Class: Memory corruption
CWE: CWE-119
CAPEC: 🔍
ATT&CK: 🔍

Physical: Partially
Local: Yes
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

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

Upgrade: iOS/iPadOS 16.4

Timelineinfo

03/08/2023 🔍
03/27/2023 +18 days 🔍
03/27/2023 +0 days 🔍
03/29/2023 +2 days 🔍
11/30/2025 +977 days 🔍

Sourcesinfo

Vendor: apple.com

Advisory: HT213676
Researcher: Ye Zhang
Status: Confirmed

CVE: CVE-2023-27956 (🔍)
GCVE (CVE): GCVE-0-2023-27956
GCVE (VulDB): GCVE-100-224341
EUVD: 🔍
scip Labs: https://www.scip.ch/en/?labs.20150917

Entryinfo

Created: 03/29/2023 09:53
Updated: 11/30/2025 03:20
Changes: 03/29/2023 09:53 (19), 03/29/2023 09:56 (28), 04/19/2023 06:37 (1), 12/12/2024 16:40 (27), 01/29/2025 17:14 (11), 04/27/2025 15:19 (3), 11/30/2025 03:20 (1)
Complete: 🔍
Cache ID: 216::103

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

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