CVE-2026-40363 Vulnerability Analysis & Exploit Details

CVE-2026-40363
Vulnerability Scoring

8.4
/10
Severe Risk

Cybersecurity professionals consider CVE-2026-40363 an immediate threat requiring urgent mitigation.

Attack Complexity Details

  • Attack Complexity: Low
    Exploits can be performed without significant complexity or special conditions.
  • Attack Vector: Local
    Vulnerability requires local system access.
  • Privileges Required: None
    No privileges are required for exploitation.
  • Scope: Unchanged
    Exploit remains within the originally vulnerable component.
  • User Interaction: None
    No user interaction is necessary for exploitation.

CVE-2026-40363 Details

Status: Analyzed

Last updated: đź•ť 22 May 2026, 14:49 UTC
Originally published on: đź•• 12 May 2026, 18:17 UTC

Time between publication and last update: 9 days

CVSS Release: version 3

CVSS3 Source

secure@microsoft.com

CVSS3 Type

Primary

CVSS3 Vector

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

CVE-2026-40363 Vulnerability Summary

CVE-2026-40363: Heap-based buffer overflow in Microsoft Office allows an unauthorized attacker to execute code locally.

Assessing the Risk of CVE-2026-40363

Access Complexity Graph

The exploitability of CVE-2026-40363 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).

Exploitability Analysis for CVE-2026-40363

With low attack complexity and no required privileges, CVE-2026-40363 is an easy target for cybercriminals. Organizations should prioritize immediate mitigation measures to prevent unauthorized access and data breaches.

Understanding AC and PR

A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.

Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.

Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.

CVSS Score Breakdown Chart

Above is the CVSS Sub-score Breakdown for CVE-2026-40363, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.

CIA Impact Analysis

Below is the Impact Analysis for CVE-2026-40363, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.

  • Confidentiality: High
    Exploiting CVE-2026-40363 can result in unauthorized access to sensitive data, severely compromising data privacy.
  • Integrity: High
    CVE-2026-40363 could allow unauthorized modifications to data, potentially affecting system reliability and trust.
  • Availability: High
    CVE-2026-40363 can disrupt system operations, potentially causing complete denial of service (DoS).

CVE-2026-40363 References

External References

CWE Common Weakness Enumeration

CWE-122

CAPEC Common Attack Pattern Enumeration and Classification

  • Forced Integer Overflow CAPEC-92 This attack forces an integer variable to go out of range. The integer variable is often used as an offset such as size of memory allocation or similarly. The attacker would typically control the value of such variable and try to get it out of range. For instance the integer in question is incremented past the maximum possible value, it may wrap to become a very small, or negative number, therefore providing a very incorrect value which can lead to unexpected behavior. At worst the attacker can execute arbitrary code.

Vulnerable Configurations

  • cpe:2.3:a:microsoft:365_apps:-:*:*:*:enterprise:*:x64:*
    cpe:2.3:a:microsoft:365_apps:-:*:*:*:enterprise:*:x64:*
  • cpe:2.3:a:microsoft:365_apps:-:*:*:*:enterprise:*:x86:*
    cpe:2.3:a:microsoft:365_apps:-:*:*:*:enterprise:*:x86:*
  • cpe:2.3:a:microsoft:365_copilot:-:*:*:*:*:*:*:*
    cpe:2.3:a:microsoft:365_copilot:-:*:*:*:*:*:*:*
  • cpe:2.3:a:microsoft:365_copilot:-:*:*:*:*:android:*:*
    cpe:2.3:a:microsoft:365_copilot:-:*:*:*:*:android:*:*
  • cpe:2.3:a:microsoft:365_copilot:2.103.0:*:*:*:*:iphone_os:*:*
    cpe:2.3:a:microsoft:365_copilot:2.103.0:*:*:*:*:iphone_os:*:*
  • cpe:2.3:a:microsoft:365_copilot:2.103.1:*:*:*:*:iphone_os:*:*
    cpe:2.3:a:microsoft:365_copilot:2.103.1:*:*:*:*:iphone_os:*:*
  • cpe:2.3:a:microsoft:365_copilot:2.103.2:*:*:*:*:iphone_os:*:*
    cpe:2.3:a:microsoft:365_copilot:2.103.2:*:*:*:*:iphone_os:*:*
  • cpe:2.3:a:microsoft:365_copilot:2.103.3:*:*:*:*:iphone_os:*:*
    cpe:2.3:a:microsoft:365_copilot:2.103.3:*:*:*:*:iphone_os:*:*
  • cpe:2.3:a:microsoft:365_copilot:2.103.4:*:*:*:*:iphone_os:*:*
    cpe:2.3:a:microsoft:365_copilot:2.103.4:*:*:*:*:iphone_os:*:*
  • cpe:2.3:a:microsoft:365_copilot:2.104:*:*:*:*:iphone_os:*:*
    cpe:2.3:a:microsoft:365_copilot:2.104:*:*:*:*:iphone_os:*:*
  • cpe:2.3:a:microsoft:365_copilot:2.104.1:*:*:*:*:iphone_os:*:*
    cpe:2.3:a:microsoft:365_copilot:2.104.1:*:*:*:*:iphone_os:*:*
  • cpe:2.3:a:microsoft:365_copilot:2.104.2:*:*:*:*:iphone_os:*:*
    cpe:2.3:a:microsoft:365_copilot:2.104.2:*:*:*:*:iphone_os:*:*
  • cpe:2.3:a:microsoft:365_copilot:2.104.3:*:*:*:*:iphone_os:*:*
    cpe:2.3:a:microsoft:365_copilot:2.104.3:*:*:*:*:iphone_os:*:*
  • cpe:2.3:a:microsoft:365_copilot:2.104.4:*:*:*:*:iphone_os:*:*
    cpe:2.3:a:microsoft:365_copilot:2.104.4:*:*:*:*:iphone_os:*:*
  • cpe:2.3:a:microsoft:365_copilot:2.104.5:*:*:*:*:iphone_os:*:*
    cpe:2.3:a:microsoft:365_copilot:2.104.5:*:*:*:*:iphone_os:*:*
  • cpe:2.3:a:microsoft:365_copilot:2.105:*:*:*:*:iphone_os:*:*
    cpe:2.3:a:microsoft:365_copilot:2.105:*:*:*:*:iphone_os:*:*
  • cpe:2.3:a:microsoft:365_copilot:2.105.1:*:*:*:*:iphone_os:*:*
    cpe:2.3:a:microsoft:365_copilot:2.105.1:*:*:*:*:iphone_os:*:*
  • cpe:2.3:a:microsoft:365_copilot:2.106:*:*:*:*:iphone_os:*:*
    cpe:2.3:a:microsoft:365_copilot:2.106:*:*:*:*:iphone_os:*:*
  • cpe:2.3:a:microsoft:365_copilot:2.106.1:*:*:*:*:iphone_os:*:*
    cpe:2.3:a:microsoft:365_copilot:2.106.1:*:*:*:*:iphone_os:*:*
  • cpe:2.3:a:microsoft:365_copilot:2.106.2:*:*:*:*:iphone_os:*:*
    cpe:2.3:a:microsoft:365_copilot:2.106.2:*:*:*:*:iphone_os:*:*
  • cpe:2.3:a:microsoft:365_copilot:2.106.3:*:*:*:*:iphone_os:*:*
    cpe:2.3:a:microsoft:365_copilot:2.106.3:*:*:*:*:iphone_os:*:*
  • cpe:2.3:a:microsoft:365_copilot:2.107:*:*:*:*:iphone_os:*:*
    cpe:2.3:a:microsoft:365_copilot:2.107:*:*:*:*:iphone_os:*:*
  • cpe:2.3:a:microsoft:365_copilot:2.107.1:*:*:*:*:iphone_os:*:*
    cpe:2.3:a:microsoft:365_copilot:2.107.1:*:*:*:*:iphone_os:*:*
  • cpe:2.3:a:microsoft:365_copilot:2.107.2:*:*:*:*:iphone_os:*:*
    cpe:2.3:a:microsoft:365_copilot:2.107.2:*:*:*:*:iphone_os:*:*
  • cpe:2.3:a:microsoft:365_copilot:2.107.3:*:*:*:*:iphone_os:*:*
    cpe:2.3:a:microsoft:365_copilot:2.107.3:*:*:*:*:iphone_os:*:*
  • cpe:2.3:a:microsoft:365_copilot:2.107.4:*:*:*:*:iphone_os:*:*
    cpe:2.3:a:microsoft:365_copilot:2.107.4:*:*:*:*:iphone_os:*:*
  • cpe:2.3:a:microsoft:365_copilot:2.108:*:*:*:*:iphone_os:*:*
    cpe:2.3:a:microsoft:365_copilot:2.108:*:*:*:*:iphone_os:*:*
  • cpe:2.3:a:microsoft:365_copilot:2.108.1:*:*:*:*:iphone_os:*:*
    cpe:2.3:a:microsoft:365_copilot:2.108.1:*:*:*:*:iphone_os:*:*
  • cpe:2.3:a:microsoft:365_copilot:2.108.2:*:*:*:*:iphone_os:*:*
    cpe:2.3:a:microsoft:365_copilot:2.108.2:*:*:*:*:iphone_os:*:*
  • cpe:2.3:a:microsoft:365_copilot:2.108.3:*:*:*:*:iphone_os:*:*
    cpe:2.3:a:microsoft:365_copilot:2.108.3:*:*:*:*:iphone_os:*:*
  • cpe:2.3:a:microsoft:365_copilot:16.0.16026.20172:*:*:*:*:android:*:*
    cpe:2.3:a:microsoft:365_copilot:16.0.16026.20172:*:*:*:*:android:*:*
  • cpe:2.3:a:microsoft:365_copilot:16.0.16130.20156:*:*:*:*:android:*:*
    cpe:2.3:a:microsoft:365_copilot:16.0.16130.20156:*:*:*:*:android:*:*
  • cpe:2.3:a:microsoft:365_copilot:16.0.16827.20138:*:*:*:*:android:*:*
    cpe:2.3:a:microsoft:365_copilot:16.0.16827.20138:*:*:*:*:android:*:*
  • cpe:2.3:a:microsoft:365_copilot:16.0.18730.20000:*:*:*:*:android:*:*
    cpe:2.3:a:microsoft:365_copilot:16.0.18730.20000:*:*:*:*:android:*:*
  • cpe:2.3:a:microsoft:365_copilot:16.0.18827.20000:*:*:*:*:android:*:*
    cpe:2.3:a:microsoft:365_copilot:16.0.18827.20000:*:*:*:*:android:*:*
  • cpe:2.3:a:microsoft:365_copilot:16.0.18925.20000:*:*:*:*:android:*:*
    cpe:2.3:a:microsoft:365_copilot:16.0.18925.20000:*:*:*:*:android:*:*
  • cpe:2.3:a:microsoft:365_copilot:16.0.19127.20000:*:*:*:*:android:*:*
    cpe:2.3:a:microsoft:365_copilot:16.0.19127.20000:*:*:*:*:android:*:*
  • cpe:2.3:a:microsoft:365_copilot:16.0.19220.20000:*:*:*:*:android:*:*
    cpe:2.3:a:microsoft:365_copilot:16.0.19220.20000:*:*:*:*:android:*:*
  • cpe:2.3:a:microsoft:365_copilot:16.0.19328.20000:*:*:*:*:android:*:*
    cpe:2.3:a:microsoft:365_copilot:16.0.19328.20000:*:*:*:*:android:*:*
  • cpe:2.3:a:microsoft:365_copilot:16.0.19426.20044:*:*:*:*:android:*:*
    cpe:2.3:a:microsoft:365_copilot:16.0.19426.20044:*:*:*:*:android:*:*
  • cpe:2.3:a:microsoft:365_copilot:16.0.19822.20000:*:*:*:*:android:*:*
    cpe:2.3:a:microsoft:365_copilot:16.0.19822.20000:*:*:*:*:android:*:*
  • cpe:2.3:a:microsoft:office:2016:*:*:*:*:*:x64:*
    cpe:2.3:a:microsoft:office:2016:*:*:*:*:*:x64:*
  • cpe:2.3:a:microsoft:office:2016:*:*:*:*:*:x86:*
    cpe:2.3:a:microsoft:office:2016:*:*:*:*:*:x86:*
  • cpe:2.3:a:microsoft:office:2019:*:*:*:*:*:x64:*
    cpe:2.3:a:microsoft:office:2019:*:*:*:*:*:x64:*
  • cpe:2.3:a:microsoft:office:2019:*:*:*:*:*:x86:*
    cpe:2.3:a:microsoft:office:2019:*:*:*:*:*:x86:*
  • cpe:2.3:a:microsoft:office_long_term_servicing_channel:2021:*:*:*:*:-:x64:*
    cpe:2.3:a:microsoft:office_long_term_servicing_channel:2021:*:*:*:*:-:x64:*
  • cpe:2.3:a:microsoft:office_long_term_servicing_channel:2021:*:*:*:*:-:x86:*
    cpe:2.3:a:microsoft:office_long_term_servicing_channel:2021:*:*:*:*:-:x86:*
  • cpe:2.3:a:microsoft:office_long_term_servicing_channel:2021:*:*:*:*:macos:*:*
    cpe:2.3:a:microsoft:office_long_term_servicing_channel:2021:*:*:*:*:macos:*:*
  • cpe:2.3:a:microsoft:office_long_term_servicing_channel:2024:*:*:*:*:-:x64:*
    cpe:2.3:a:microsoft:office_long_term_servicing_channel:2024:*:*:*:*:-:x64:*
  • cpe:2.3:a:microsoft:office_long_term_servicing_channel:2024:*:*:*:*:-:x86:*
    cpe:2.3:a:microsoft:office_long_term_servicing_channel:2024:*:*:*:*:-:x86:*
  • cpe:2.3:a:microsoft:office_long_term_servicing_channel:2024:*:*:*:*:macos:*:*
    cpe:2.3:a:microsoft:office_long_term_servicing_channel:2024:*:*:*:*:macos:*:*

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