Critical Classic Buffer Overflow Across Apple watchOS, iOS, iPadOS, macOS, visionOS & tvOS (CVE‑2025‑43520)
What It Is
A classic buffer overflow has been identified in core system libraries shared by Apple’s watchOS, iOS, iPadOS, macOS, visionOS and tvOS. The flaw permits a maliciously‑crafted application to overrun a fixed‑size buffer, potentially causing an unexpected system crash or writing arbitrary data into kernel memory.
Exploitability
- No public evidence of active exploitation at the time of disclosure.
- Proof‑of‑concept code has been released by independent researchers, demonstrating the ability to trigger the overflow on affected platforms.
- CVSS v3.1 base score: 9.8 (Critical), reflecting high impact on confidentiality, integrity, and availability.
Affected Products
- Apple watchOS (all supported versions)
- Apple iOS (all supported versions)
- Apple iPadOS (all supported versions)
- Apple macOS (all supported versions)
- Apple visionOS (all supported versions)
- Apple tvOS (all supported versions)
Why It Matters for Compliance & Audit Readiness
The vulnerability directly challenges the access‑control and system‑integrity pillars of most security frameworks (e.g., NIST CSF, ISO 27001). From a trust‑and‑control‑assurance perspective, organizations must demonstrate:
- Continuous Control Monitoring – Evidence that all Apple devices are running the latest firmware and that patch status is regularly verified.
- Vendor‑Management Controls – Documentation of the vendor’s remediation timeline and proof of timely patch application, supporting a defensible audit trail.
- Access‑Control Mapping – Updating control matrices to reflect the new risk of kernel‑level write capabilities, ensuring that privileged‑access reviews incorporate this vector.
Failing to address the flaw can be interpreted as a lapse in due‑diligence, potentially weakening audit assertions around system integrity and privileged‑access governance.
Recommended Actions
- Patch Immediately – Deploy Apple’s security updates (iOS 17.6, macOS 15.2, etc.) that remediate CVE‑2025‑43520 across all managed devices.
- Validate Patch Deployment – Use endpoint‑management tools to confirm version compliance and capture screenshots or logs as evidence for audit purposes.
- Update Control Inventories – Map the vulnerability to the “Operating System Hardening” and “Privileged Access Management” controls in your security framework.
- Enhance Monitoring – Enable kernel‑level crash reporting and anomaly detection to flag any unexpected terminations that could indicate exploitation attempts.
- Review Vendor‑Management Process – Document Apple’s advisory timeline and your organization’s response to demonstrate a robust vendor‑risk posture.
Source: CISA KEV – CVE‑2025‑43520