SB2026061046 - Multiple vulnerabilities in Microsoft Excel
Published: June 10, 2026
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 8 vulnerabilities.
1) Integer underflow (CVE-ID: CVE-2026-45469)
CWE-ID: CWE-191 - Integer underflow
CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber
The vulnerability allows a remote attacker to execute arbitrary code on the target system.
The vulnerability exists due to integer underflow in Microsoft Excel. A remote attacker can trick a victim to open a specially crafted Office file, trigger integer underflow and execute arbitrary code on the target system.
Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.
2) Protection Mechanism Failure (CVE-ID: CVE-2026-45459)
CWE-ID: CWE-693 - Protection Mechanism Failure
CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
The vulnerability allows a remote attacker to bypass implemented security restrictions.
The vulnerability exists due to insufficient implementation of security measures in Microsoft Excel. A remote attacker can trick a victim to open a specially crafted Office file, bypass implemented security restrictions and gain access to sensitive information.
3) Out-of-bounds read (CVE-ID: CVE-2026-45455)
CWE-ID: CWE-125 - Out-of-bounds read
CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
The vulnerability allows a remote attacker to gain access to potentially sensitive information.
The vulnerability exists due to a boundary condition in Microsoft Excel. A remote attacker can create a specially crafted Office file, trick the victim into opening it, trigger an out-of-bounds read error and read contents of memory on the system.
4) Out-of-bounds read (CVE-ID: CVE-2026-44822)
CWE-ID: CWE-125 - Out-of-bounds read
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
The vulnerability allows a remote attacker to gain access to potentially sensitive information.
The vulnerability exists due to a boundary condition in Microsoft Excel. A remote attacker can trigger an out-of-bounds read error and read contents of memory on the system.
5) Integer underflow (CVE-ID: CVE-2026-44823)
CWE-ID: CWE-191 - Integer underflow
CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber
The vulnerability allows a remote attacker to execute arbitrary code on the target system.
The vulnerability exists due to integer underflow in Microsoft Excel. A remote attacker can trick a victim to open a specially crafted Office file, trigger integer underflow and execute arbitrary code on the target system.
Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.
6) Integer underflow (CVE-ID: CVE-2026-44820)
CWE-ID: CWE-191 - Integer underflow
CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber
The vulnerability allows a remote attacker to execute arbitrary code on the target system.
The vulnerability exists due to integer underflow in Microsoft Excel. A remote attacker can trick a victim to open a specially crafted Office file, trigger integer underflow and execute arbitrary code on the target system.
Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.
7) Integer underflow (CVE-ID: CVE-2026-44818)
CWE-ID: CWE-191 - Integer underflow
CVSSv4: CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber
The vulnerability allows a remote attacker to execute arbitrary code on the target system.
The vulnerability exists due to integer underflow in Microsoft Excel. A remote attacker can trick a victim to open a specially crafted Office file, trigger integer underflow and execute arbitrary code on the target system.
Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.
8) Integer underflow (CVE-ID: CVE-2026-44817)
CWE-ID: CWE-191 - Integer underflow
CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber
The vulnerability allows a remote attacker to execute arbitrary code on the target system.
The vulnerability exists due to integer underflow in Microsoft Excel. A remote attacker can trick a victim to open a specially crafted Office file, trigger integer underflow and execute arbitrary code on the target system.
Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.
Remediation
Install update from vendor's website.
References
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-45469
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-45459
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-45455
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-44822
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-44823
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-44820
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-44818
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-44817