Out-of-bounds read in Microsoft Office Excel 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 june-16-2026 advisory.

  - Heap-based buffer overflow in Microsoft Office allows an unauthorized attacker to execute code locally.
    (CVE-2026-44819, CVE-2026-44824, CVE-2026-45461, CVE-2026-45463, CVE-2026-45472, CVE-2026-45474,     CVE-2026-45475, CVE-2026-45645)

  - Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker to disclose information over     a network. (CVE-2026-44822, CVE-2026-45455)

  - Integer underflow (wrap or wraparound) in Microsoft Office Excel allows an unauthorized attacker to     execute code locally. (CVE-2026-44817, CVE-2026-44818, CVE-2026-44820, CVE-2026-44823, CVE-2026-45469)

  - Protection mechanism failure in Microsoft Office Excel allows an unauthorized attacker to bypass a     security feature locally. (CVE-2026-45459)

  - Out-of-bounds read in Microsoft Office allows an unauthorized attacker to disclose information locally.
    (CVE-2026-44821, CVE-2026-45460, CVE-2026-45485)

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

The Microsoft Excel Products are missing security updates. It is, therefore, affected by multiple vulnerabilities:

  - Integer underflow (wrap or wraparound) in Microsoft Office Excel allows an unauthorized attacker to     execute code locally. (CVE-2026-44817, CVE-2026-44818, CVE-2026-44820, CVE-2026-44823, CVE-2026-45469)

  - Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker to disclose information     over a network. (CVE-2026-44822, CVE-2026-45455)

  - Protection mechanism failure in Microsoft Office Excel allows an unauthorized attacker to bypass a     security feature locally. (CVE-2026-45459)

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

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

  - Integer underflow (wrap or wraparound) in Microsoft Office Excel allows an unauthorized attacker to     execute code locally. (CVE-2026-44817, CVE-2026-44818, CVE-2026-44820, CVE-2026-44823, CVE-2026-45469)

  - Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker to disclose information     over a network. (CVE-2026-44822, CVE-2026-45455)

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

The Microsoft Office Online Server or Office Web Apps installation on the remote host is missing security updates. It is, therefore, affected by multiple vulnerabilities:

  - Integer underflow (wrap or wraparound) in Microsoft Office Excel allows an unauthorized attacker to execute     code locally. (CVE-2026-44817, CVE-2026-44818, CVE-2026-44820, CVE-2026-44823, CVE-2026-45469)

  - Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker to disclose information over     a network. (CVE-2026-44822, CVE-2026-45455)

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
321311	Security Updates for Microsoft Office Products (June 2026) (macOS)	Nessus	MacOS X Local Security Checks	Local	medium
320865	Security Updates for Microsoft Excel Products C2R (June 2026)	Nessus	Windows	Local	medium
320185	Security Updates for Microsoft Excel Products (June 2026)	Nessus	Windows : Microsoft Bulletins	Local	medium
320183	Security Updates for Microsoft Office Online Server (June 2026)	Nessus	Windows : Microsoft Bulletins	Local	medium

Detections

Analytics

CVE-2026-44820

high

Tenable Plugins

medium

medium

medium

medium