What is the CVSS score of CVE-2026-20639?

CVE-2026-20639 has a CVSS 3.1 base score of 7.5 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. EPSS exploitation probability: 0.0%.

Which versions of macOS are affected by CVE-2026-20639?

Apple macOS versions Sequoia 15.7.4 and earlier, Sonoma 14.8.4 and earlier, and Tahoe 26.2 and earlier contain a high-severity integer overflow vulnerability that enables remote denial of service and…. A patch is available.

How to fix or mitigate CVE-2026-20639?

Within 24 hours: Inventory all macOS systems running Sequoia ≤15.7.4, Sonoma ≤14.8.4, or Tahoe ≤26.2; identify business-critical systems. Within 7 days: Apply vendor-released security updates to non-production systems first (Sequoia 15.7.5+, Sonoma 14.8.5+, Tahoe 26.3+) and validate functionality. Within 30 days: Complete patching of all remaining macOS endpoints and validate completion via Mobile Device Management (MDM) or endpoint detection systems.

macOS CVE-2026-20639

EUVD-2026-15043 HIGH

Integer Overflow or Wraparound (CWE-190)

2026-03-25 apple

GHSA-7gg2-3r7f-v522

Apple Integer Overflow Buffer Overflow macOS

7.5

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

7.5 HIGH

AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Lifecycle Timeline

Analysis Updated

Apr 16, 2026 - 06:16 EUVD-patch-fix

executive_summary

Re-analysis Queued

Apr 16, 2026 - 05:29 backfill_euvd_patch

patch_released

Patch available

Apr 16, 2026 - 05:29 EUVD

14.8.5,15.7.5,26.3

EUVD ID Assigned

Mar 25, 2026 - 01:00 euvd

EUVD-2026-15043

Analysis Generated

Mar 25, 2026 - 01:00 vuln.today

CVE Published

Mar 25, 2026 - 00:32 nvd

HIGH 7.5

DescriptionCVE.org

An integer overflow was addressed with improved input validation. This issue is fixed in macOS Sequoia 15.7.5, macOS Sonoma 14.8.5, macOS Tahoe 26.3. Processing a maliciously crafted string may lead to heap corruption.

AnalysisAI

Integer overflow vulnerability in Apple macOS (Sequoia 15.7.4 and earlier, Sonoma 14.8.4 and earlier, Tahoe 26.2 and earlier) allows remote attackers to trigger heap corruption by processing a specially crafted string without requiring user interaction or privileges. The vulnerability results in denial of service and potential memory corruption but currently lacks a public patch. No active exploitation has been reported.

Technical ContextAI

The vulnerability involves an integer overflow in string processing logic within macOS core components, affecting Apple's macOS operating system across multiple versions as indicated by the CPE string cpe:2.3:a:apple:macos:*:*:*:*:*:*:*:*. The root cause relates to insufficient input validation during integer calculations, falling under the category of integer overflow/wraparound vulnerabilities. When a maliciously crafted string is processed, the integer overflow causes a buffer to be allocated with an incorrect size, leading to heap corruption when the undersized buffer is written to, potentially allowing memory disclosure or code execution depending on heap layout and subsequent operations.

RemediationAI

Immediately upgrade to macOS Sequoia 15.7.5, macOS Sonoma 14.8.5, or macOS Tahoe 26.3 or later, depending on which operating system version is in use. Users should check the Apple security advisories at https://support.apple.com/en-us/126348, https://support.apple.com/en-us/126795, and https://support.apple.com/en-us/126796 for complete patch details and enable automatic security updates if not already enabled. For enterprise deployments, prioritize patching systems that process untrusted string input from network sources, and consider network-level monitoring for exploitation attempts involving malformed string data.