Cyber Resilience

CVE-2025-43343

Memory Safety in Apple Safari ≤ 26.0

Memory Safety
Published
15 September 2025
Modified
02 April 2026
Patch / advisory
View advisory
CVSS Score v3.1 9.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0072 51th percentile
Risk Priority 72 floored blend · peak EPSS

Summary

CVE-2025-43343 is a critical-severity Improper Restriction of Operations within the Bounds of a Memory Buffer (CWE-119) vulnerability in Apple Safari. Its CVSS base score is 9.8 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Process Injection (T1055); ranked in the top 49% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SA-8 (Security and Privacy Engineering Principles) and SI-10 (Information Input Validation) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2025-43343 is a memory handling vulnerability classified under CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer). It affects Apple's Safari browser and WebKit rendering engine across multiple platforms, including Safari 26, iOS 26 and iPadOS 26, macOS Tahoe 26, tvOS 26, visionOS 26, and watchOS 26. The issue arises when processing maliciously crafted web content, which may lead to an unexpected process crash. The vulnerability carries a CVSS v3.1 base score of 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H), marking it as critical.

Any remote attacker can exploit this vulnerability without authentication, privileges, or user interaction, simply by having a targeted user load malicious web content in an affected browser or app. Exploitation occurs over the network with low complexity, potentially granting high impacts on confidentiality, integrity, and availability as scored by CVSS, despite the described outcome of a process crash.

Apple has addressed the vulnerability through improved memory handling in the listed fixed versions of Safari 26, iOS 26 and iPadOS 26, macOS Tahoe 26, tvOS 26, visionOS 26, and watchOS 26. Security practitioners should ensure systems are updated to these versions. Additional details are provided in Apple's security advisories at https://support.apple.com/en-us/125108, https://support.apple.com/en-us/125110, https://support.apple.com/en-us/125113, https://support.apple.com/en-us/125114, and https://support.apple.com/en-us/125115.

EU & UK References

Vulnerability Data

The issue was addressed with improved memory handling. This issue is fixed in Safari 26, iOS 26 and iPadOS 26, macOS Tahoe 26, tvOS 26, visionOS 26, watchOS 26. Processing maliciously crafted web content may lead to an unexpected process…

more

crash.

CWE(s)
CWE-119

Related Threats

MITRE ATT&CK Enterprise Techniques

T1055 Process Injection Stealth
Adversaries may inject code into processes in order to evade process-based defenses as well as possibly elevate privileges.
attack.mitre.org →
T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
attack.mitre.org →
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
attack.mitre.org →
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
attack.mitre.org →
T1212 Exploitation for Credential Access Credential Access
Adversaries may exploit software vulnerabilities in an attempt to collect credentials.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2025-43342Same product: Apple Ipados
CVE-2024-27851Same product: Apple Ipados
CVE-2025-24189Same product: Apple Ipados
CVE-2025-31257Same product: Apple Ipados
CVE-2025-43212Same product: Apple Ipados
CVE-2024-54551Same product: Apple Ipados
CVE-2025-31204Same product: Apple Ipados
CVE-2025-46298Same product: Apple Ipados
CVE-2024-27820Same product: Apple Ipados
CVE-2025-31273Same product: Apple Ipados

Affected Assets

apple
safari
≤ 26.0
apple
ipados
≤ 26.0
apple
iphone os
≤ 26.0
apple
macos
≤ 26.0
apple
tvos
≤ 26.0
apple
visionos
≤ 26.0
apple
watchos
≤ 26.0
webkitgtk
webkitgtk
≤ 2.50.1
wpewebkit
wpe webkit
≤ 2.50.1

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V17.3.2

Mitigating Controls (NIST 800-53 r5) AI

SA-8 Security and Privacy Engineering Principles partial match

Secure engineering principles require memory-safe design and coding that structurally avoids buffer-boundary violations.

SI-10 Information Input Validation partial match

Input validation directly enforces bounds checking that stops out-of-bounds reads/writes from being introduced or reached.

SI-16 Memory Protection partial match

Memory protection restricts exploitation impact of buffer overflows without eliminating the underlying coding flaw.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices (bounds checking, safe APIs, reviews) directly prevent this class of flaw.

ID.RA-01 partial match
prevents

Vulnerability scanning and code analysis directly surface buffer-boundary flaws.

ID.RA-08 partial match
prevents

Receiving and triaging vulnerability disclosures commonly includes buffer-related reports.

PR.AT-02 partial match
prevents

Developer training on secure coding reduces introduction of memory-buffer errors.

PR.PS-02 partial match
prevents

Patching replaces vulnerable code containing buffer-boundary defects.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.29 Security testing in development and acceptance mostly match
finds

Security testing in development catches out-of-bounds accesses before release, covering most instances of the weakness.

A.8.25 Secure development life cycle partial match
prevents

Secure development lifecycle mandates memory-safety practices that directly prevent buffer-boundary violations.

A.8.26 Application security requirements partial match
prevents

Application security requirements can specify memory-safety rules, but do not prescribe implementation details.

A.8.27 Secure system architecture and engineering principles partial match
prevents

Secure architecture and engineering principles include memory-safe design patterns that mitigate buffer overflows.

A.8.28 Secure coding partial match
prevents

Secure coding standards explicitly forbid unsafe buffer operations, directly eliminating CWE-119.

References