What is the CVSS score of CVE-2026-39877?

CVE-2026-39877 has a CVSS 3.1 base score of 7.8 (High). CVSS vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H. EPSS exploitation probability: 0.2%.

Which versions of Apple are affected by CVE-2026-39877?

A memory corruption vulnerability in the macOS kernel (CVE-2026-39877) could allow a local app to disclose kernel memory, potentially aiding further attacks.. A patch is available.

How to fix or mitigate CVE-2026-39877?

Within 24 hours, begin testing the vendor-released patches for macOS Sequoia 15.7.8 and Sonoma 14.8.8 in a controlled environment. Within 7 days, deploy these patches to all managed macOS systems, prioritizing high-risk users. Within 30 days, verify patch compliance across all endpoints and review endpoint detection rules for any unusual kernel-level access attempts.

Apple CVE-2026-39877

EUVD-2026-49520 HIGH

Buffer Overflow (CWE-119)

2026-07-27 apple

GHSA-hvwx-8xwj-pgx8

Buffer Overflow Apple

7.8

CVSS 3.1 · Vendor: apple

Severity by source

Vendor (apple) PRIMARY

7.8 HIGH

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

Primary rating from Vendor (apple) · only source for this CVE.

CVSS VectorVendor: apple

Attack Vector

Local

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

Analysis Generated

Jul 28, 2026 - 15:24 vuln.today

CVSS changed

Jul 28, 2026 - 15:22 NVD

7.8 (HIGH)

Patch available

Jul 27, 2026 - 21:17 EUVD

CVE Published

Jul 27, 2026 - 20:13 cve.org

HIGH 7.8

CVE Published

Jul 27, 2026 - 20:13 cve.org

UNKNOWN (no severity yet)

DescriptionCVE.org

A memory corruption issue was addressed with improved memory handling. This issue is fixed in macOS Sequoia 15.7.8, macOS Sonoma 14.8.8. An app may be able to disclose kernel memory.

AnalysisAI

Memory corruption in the macOS kernel allows a local app to disclose kernel memory, potentially enabling further exploitation. Fixed in macOS Sequoia 15.7.8 and Sonoma 14.8.8, the vulnerability requires user interaction but no elevated privileges. No public exploit code or active exploitation has been identified, and the EPSS probability is very low (0.15%).