What is CVE-2025-43520?

CVE-2025-43520 is a medium-severity vulnerability in Apple iOS And Ipados, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 5.5/10. Published 2025-12-12.

How severe is CVE-2025-43520?

Medium severity. CVSS v3 base score is 5.5 out of 10.

Is CVE-2025-43520 known to be exploited?

Yes. CVE-2025-43520 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2026-03-20), indicating it is being actively exploited.

Buffer overflow in Apple iOS And Ipados

CVE-2025-43520

A memory corruption issue was addressed with improved memory handling. This issue is fixed in iOS 18.7.2 and iPadOS 18.7.2, iOS 26.1 and iPadOS 26.1, macOS Sequoia 15.7.2, macOS Sonoma 14.8.2, macOS Tahoe 26.1, tvOS 26.1, visionOS 26.1, watchOS 26.1. A malicious application may be able to cause unexpected system termination or write kernel memory.

Vulnerability class: Buffer Overflow

Published 2025-12-12 · last modified 2026-10-07.

CVSS v3 metric

CVSS v3 base score 5.5 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.004 (35.3th percentile), scored 2026-10-19.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 35th percentile — 35.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000

Affected products

Apple iOS And Ipados — versions 0
Apple Ipados — versions 26.0
Apple Iphone OS — versions 26.0
Apple macOS — versions 26.0, 0
Apple tvOS — versions 0
Apple Visionos — versions 0
Apple watchOS — versions 0

Weakness classification (CWE)

CWE-120 — Buffer Copy without Checking Size of Input (Classic Buffer Overflow)

CISA KEV (Known Exploited Vulnerabilities)

This CVE is on the CISA KEV catalog, added on 2026-03-20. CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.

BOD 22-01 due date: 2026-04-03.

Required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

References

support.apple.com/en-us/125632 (Release Notes, Vendor Advisory)
support.apple.com/en-us/125633 (Release Notes, Vendor Advisory)
support.apple.com/en-us/125634 (Release Notes, Vendor Advisory)
support.apple.com/en-us/125635 (Release Notes, Vendor Advisory)
support.apple.com/en-us/125636 (Release Notes, Vendor Advisory)
support.apple.com/en-us/125637 (Release Notes, Vendor Advisory)
support.apple.com/en-us/125638 (Release Notes, Vendor Advisory)
support.apple.com/en-us/125639 (Release Notes, Vendor Advisory)
134c704f-9b21-4f2e-91b3-4a467353bcc0 (Technical Description)
134c704f-9b21-4f2e-91b3-4a467353bcc0 (US Government Resource)

Frequently asked questions

What is CVE-2025-43520?: CVE-2025-43520 is a medium-severity vulnerability in Apple iOS And Ipados, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 5.5/10. Published 2025-12-12.
How severe is CVE-2025-43520?: Medium severity. CVSS v3 base score is 5.5 out of 10.
Is CVE-2025-43520 known to be exploited?: Yes. CVE-2025-43520 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2026-03-20), indicating it is being actively exploited.