CVE-2026-40358

⚠️ high

🔍 Scan for this CVE

Heap-based buffer overflow in Microsoft Office allows an unauthorized attacker to execute code locally.

CVSS Score

8.4

High

EPSS Score

0.1

Exploit Probability

Published Date

2026-05-12

First Seen: 2026-05-20

This CVE is High Risk - more severe than 80.3% of all 326,604 vulnerabilities in our database.

#64,269

Top 25% most severe

Severity Percentile

🔍 Exploitation Status

None

No known exploits

⚙️ Automatable

Requires human interaction

💥 Technical Impact

Total

Complete system compromise possible

SSVC data provided by CISA

Last Modified 2026-06-01

Source NVD 🔗

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

CWE IDs (Weakness Types)

CWE-416

📦 Affected Products 5

Vendor	Product	Status	Affected Versions
microsoft	office	Affected	v2016
microsoft	office	Affected	v2019
microsoft	365_apps	Affected	v-
microsoft	office_long_term_servicing_channel	Affected	v2021
microsoft	office_long_term_servicing_channel	Affected	v2024

Vendor Advisory

CVE ID	Severity	CVSS	EPSS	Summary	Published
CVE-2026-40421	🔶 medium	4.3	0.1	Files or directories accessible to external parties in Microsoft Office Word allows an unauthorized attacker to disclose...	2026-05-12
CVE-2026-42831	⚠️ high	7.8	0.1	Heap-based buffer overflow in Microsoft Office allows an unauthorized attacker to execute code locally.	2026-05-12
CVE-2026-42832	⚠️ high	7.7	0.1	Improper access control in Microsoft Office allows an unauthorized attacker to perform spoofing locally.	2026-05-12
CVE-2026-35436	⚠️ high	8.8	0.1	Use after free in Microsoft Office allows an authorized attacker to elevate privileges locally.	2026-05-12
CVE-2026-35440	🔶 medium	5.5	0.0	Files or directories accessible to external parties in Microsoft Office Word allows an unauthorized attacker to disclose...	2026-05-12
CVE-2026-40359	⚠️ high	7.8	0.1	Use after free in Microsoft Office Excel allows an unauthorized attacker to execute code locally.	2026-05-12

These CVEs affect the same products