VDB-374720 · CVE-2026-43663 · Nessus 323673

Apple Safari/iOS/iPadOS/macOS up to 26.5.1 Web denial of service

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.
5.3	$5k-$25k	0.62

Summaryinfo

A vulnerability labeled as problematic has been found in Apple Safari, iOS, iPadOS and macOS up to 26.5.1. Impacted is an unknown function of the component Web Handler. Such manipulation leads to denial of service. This vulnerability is referenced as CVE-2026-43663. It is possible to launch the attack remotely. No exploit is available. The affected component should be upgraded.

Detailsinfo

A vulnerability was found in Apple Safari, iOS, iPadOS and macOS up to 26.5.1 and classified as problematic. Affected by this issue is an unknown part of the component Web Handler. The manipulation with an unknown input leads to a denial of service vulnerability. Using CWE to declare the problem leads to CWE-404. The product does not release or incorrectly releases a resource before it is made available for re-use. Impacted is availability. CVE summarizes:

The issue was addressed with improved memory handling. This issue is fixed in Safari 26.5.2, iOS 26.5.2 and iPadOS 26.5.2, macOS Tahoe 26.5.2. Processing maliciously crafted web content may lead to an unexpected process crash.

The advisory is shared for download at support.apple.com. This vulnerability is handled as CVE-2026-43663 since 05/02/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. Successful exploitation requires user interaction by the victim. There are neither technical details nor an exploit publicly available. The current price for an exploit might be approx. USD $5k-$25k (estimation calculated on 06/30/2026). The MITRE ATT&CK project declares the attack technique as T1499.

The vulnerability scanner Nessus provides a plugin with the ID 323673 (macOS 26.x < 26.5.2 Multiple Vulnerabilities (127595)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 26.5.2 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (323673). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Type

Web Browser

Vendor

Apple

Name

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: 5.4
VulDB Meta Temp Score: 5.3

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

ADP CISA Base Score: 6.5
ADP CISA Vector: 🔒

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: Denial of service
CWE: CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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

Nessus ID: 323673
Nessus Name: macOS 26.x < 26.5.2 Multiple Vulnerabilities (127595)

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Safari/iOS/iPadOS/macOS 26.5.2

Timelineinfo

05/02/2026 CVE reserved
06/29/2026 +58 days VulDB entry created
06/30/2026 +0 days Advisory disclosed
06/30/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: apple.com

Advisory: support.apple.com
Status: Confirmed

CVE: CVE-2026-43663 (🔒)
GCVE (CVE): GCVE-0-2026-43663
GCVE (VulDB): GCVE-100-374720
scip Labs: https://www.scip.ch/en/?labs.20180712

Entryinfo

Created: 06/30/2026 01:02
Updated: 06/30/2026 08:27
Changes: 06/30/2026 01:02 (66), 06/30/2026 08:27 (2)
Complete: 🔍
Cache ID: 216::103

VulDB is the best source for vulnerability data and more expert information about this specific topic.