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

The version of Microsoft Office for Mac installed on the remote host is affected by multiple vulnerabilities as referenced in the august-11-2026 advisory.

  - Use after free in Microsoft Office Word allows an unauthorized attacker to execute code locally.
    (CVE-2026-70311)

  - Access of resource using incompatible type ('type confusion') in Microsoft Office Excel allows an     unauthorized attacker to execute code over a network. (CVE-2026-65807)

  - Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker to execute code locally.
    (CVE-2026-68793, CVE-2026-68814)

  - Heap-based buffer overflow in Microsoft Office Excel allows an unauthorized attacker to execute code     locally. (CVE-2026-68794, CVE-2026-68796, CVE-2026-68798, CVE-2026-68800, CVE-2026-68801, CVE-2026-68805,     CVE-2026-68807, CVE-2026-68812, CVE-2026-68815)

  - Stack-based buffer overflow in Microsoft Office Excel allows an unauthorized attacker to execute code     locally. (CVE-2026-68795, CVE-2026-68816, CVE-2026-68817)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The Microsoft Outlook Products are missing a security update. They are, therefore, affected by multiple vulnerabilities:

  - Integer overflow or wraparound in Microsoft Office Outlook allows an unauthorized attacker to     execute code over a network. (CVE-2026-70329)

  - Heap-based buffer overflow in Microsoft Office Word allows an unauthorized attacker to execute     code locally. (CVE-2026-63518)

  - Insufficiently protected credentials in Microsoft Office Outlook allows an unauthorized attacker     to perform spoofing over a network. (CVE-2026-62882)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

ID	Name	Product	Family	Type	Severity
334691	Security Updates for Microsoft Office Products (August 2026) (macOS)	Nessus	MacOS X Local Security Checks	Local	high
334615	Security Updates for Microsoft Outlook Products (August 2026)	Nessus	Windows : Microsoft Bulletins	Local	high

Detections

Analytics

CVE-2026-63518

high

Tenable Plugins

high

high