Cyber Resilience

CVE-2026-20664

MediumUpdated

Published: 25 March 2026

Published
25 March 2026
Modified
30 June 2026
KEV Added
Patch
CVSS Score v3.1 4.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
EPSS Score 0.0047 37.4th percentile
Risk Priority 35 floored blend · peak EPSS

Summary

CVE-2026-20664 is a medium-severity Out-of-bounds Write (CWE-787) vulnerability in Apple Safari. Its CVSS base score is 4.3 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Application or System Exploitation (T1499.004); ranked at the 37.4th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability details

The issue was addressed with improved memory handling. This issue is fixed in Safari 26.4, iOS 26.4 and iPadOS 26.4, macOS Tahoe 26.4, visionOS 26.4. Processing maliciously crafted web content may lead to an unexpected process crash.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1499.004 Application or System Exploitation Impact
Adversaries may exploit software vulnerabilities that can cause an application or system to crash and deny availability to users.
Why these techniques?

CWE-787 out-of-bounds write triggered by crafted web content in Safari causes process crash, directly enabling application DoS via exploitation.

Confidence: MEDIUM · MITRE ATT&CK Enterprise v19.0

Affected Assets

apple
safari
≤ 26.4
apple
ipados
≤ 26.4
apple
iphone os
≤ 26.4
apple
macos
26.0 — 26.4
apple
visionos
≤ 26.4

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-120

Platform-independent managed code eliminates the need for unchecked native buffer copies that are the root cause of classic buffer overflows.

addresses: CWE-787

Out-of-bounds writes that corrupt control flow or inject shellcode are rendered non-executable by the same memory protections.

References