Quantum Secular Labs / Blog / Advisories
CVE-2025-43300: Apple iOS, iPadOS, and macOS Out-of-Bounds Write Vulnerability
CVE-2025-43300 is rated critical with a CVSS v3.1 base score of 10.0 and affects Apple iOS, iPadOS, and macOS, along with 1 other product in NVD’s configuration data. Per its scoring, it can be exploited over the network, without authentication, without any user interaction. The scored impact on confidentiality, integrity and availability is the highest available. CISA added it to its Known Exploited Vulnerabilities catalog on 2025-08-21, which means exploitation in the wild has been observed.
Vulnerability description
An out-of-bounds write issue was addressed with improved bounds checking. This issue is fixed in iOS 15.8.5 and iPadOS 15.8.5, iOS 16.7.12 and iPadOS 16.7.12, iOS 18.6.2 and iPadOS 18.6.2, iPadOS 17.7.10, macOS Sequoia 15.6.1, macOS Sonoma 14.7.8, macOS Ventura 13.7.8. Processing a malicious image file may result in memory corruption. Apple is aware of a report that this issue may have been exploited in an extremely sophisticated attack against specific targeted individuals.
Severity breakdown
CVSS v3.1 10.0: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
- Attack vector: Network. Exploitable remotely over the network, with no need for local or physical access.
- Attack complexity: Low. No special conditions; the attack can be repeated reliably.
- Privileges required: None. No account or prior access is needed.
- User interaction: None. No action from any user is needed.
- Scope: Changed. Impact reaches beyond the vulnerable component to other resources.
- Confidentiality impact: High. Total loss of confidentiality; sensitive data can be fully disclosed.
- Integrity impact: High. Total loss of integrity; data or system state can be fully modified.
- Availability impact: High. Total loss of availability; the component can be shut down.
Underlying weakness
CWE-787: Out-of-bounds Write
The product writes data past the end, or before the beginning, of the intended buffer.
Affected products
- Apple Ipados: before 15.8.5; from 16.0 before 16.7.12; from 17.0 before 17.7.10; from 18.0 before 18.6.2
- Apple macOS: from 13.0 before 13.7.8; from 14.0 before 14.7.8; from 15.0 before 15.6.1
- Apple Iphone OS: before 15.8.5; from 16.0 before 16.7.12; from 17.0 before 18.6.2
References
- https://support.apple.com/en-us/124925
- https://support.apple.com/en-us/124926
- https://support.apple.com/en-us/124927
- https://support.apple.com/en-us/124928
- https://support.apple.com/en-us/124929
- https://support.apple.com/en-us/125141
- https://support.apple.com/en-us/125142
- http://seclists.org/fulldisclosure/2025/Sep/10
- http://seclists.org/fulldisclosure/2025/Sep/14
- http://seclists.org/fulldisclosure/2025/Sep/52
- https://github.com/b1n4r1b01/n-days/blob/main/CVE-2025-43300.md
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-43300
- https://github.com/cisagov/vulnrichment/issues/201