How severe is CVE-2026-45459?

CVE-2026-45459 has a CVSS 3.x base score of 3.3, rated low severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity none, and availability none.

Is CVE-2026-45459 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (29th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-45459?

CVE-2026-45459 primarily affects Microsoft 365 Apps. In total, 7 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-45459?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-45459 have an EU (EUVD) identifier?

Yes. CVE-2026-45459 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-35541.

When was CVE-2026-45459 published?

CVE-2026-45459 was published on 2026-06-09 and last updated on 2026-06-19.

CVE-2026-45459

CVE-2026-45459 is a low-severity vulnerability in Microsoft 365 Apps with a CVSS 3.x base score of 3.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-693.

Key facts

Severity: Low (CVSS 3.x base score 3.3)
EPSS exploit prediction: 0% (29th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-35541
Weakness: CWE-693
Affected product: Microsoft 365 Apps
Published: 2026-06-09
Last modified: 2026-06-19

Description

Protection mechanism failure in Microsoft Office Excel allows an unauthorized attacker to bypass a security feature locally.

Frequently asked questions

What is CVE-2026-45459?: Protection mechanism failure in Microsoft Office Excel allows an unauthorized attacker to bypass a security feature locally.
How severe is CVE-2026-45459?: CVE-2026-45459 has a CVSS 3.x base score of 3.3, rated low severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity none, and availability none.
Is CVE-2026-45459 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (29th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-45459?: CVE-2026-45459 primarily affects Microsoft 365 Apps. In total, 7 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-45459?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-45459 have an EU (EUVD) identifier?: Yes. CVE-2026-45459 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-35541.
When was CVE-2026-45459 published?: CVE-2026-45459 was published on 2026-06-09 and last updated on 2026-06-19.

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-45459

Affected products (7)

cpe:2.3:a:microsoft:365_apps:-:*:*:*:enterprise:*:x64:*
cpe:2.3:a:microsoft:365_apps:-:*:*:*:enterprise:*:x86:*
cpe:2.3:a:microsoft:microsoft_365:-:*:*:*:*:macos:*:*
cpe:2.3:a:microsoft:office_2021:-:*:*:*:ltsc:macos:-:*
cpe:2.3:a:microsoft:office_2024:-:*:*:*:ltsc:-:x64:*
cpe:2.3:a:microsoft:office_2024:-:*:*:*:ltsc:-:x86:*
cpe:2.3:a:microsoft:office_2024:-:*:*:*:ltsc:macos:-:*

More vulnerabilities in Microsoft 365 Apps

CVE-2024-21413 — Critical (CVSS 9.8): Microsoft Outlook Remote Code Execution Vulnerability
CVE-2023-23397 — Critical (CVSS 9.8): Microsoft Outlook Elevation of Privilege Vulnerability
CVE-2020-0901 — Critical (CVSS 9.8): A remote code execution vulnerability exists in Microsoft Excel software when the software fails to properly handle…
CVE-2023-33150 — Critical (CVSS 9.6): Microsoft Office Security Feature Bypass Vulnerability
CVE-2026-40420 — High (CVSS 8.8): Use after free in Microsoft Office allows an authorized attacker to elevate privileges locally.
CVE-2026-35436 — High (CVSS 8.8): Use after free in Microsoft Office allows an authorized attacker to elevate privileges locally.

All CVEs affecting Microsoft 365 Apps →

Other CWE-693 (Protection Mechanism Failure) vulnerabilities

CVE-2026-47140 — Critical (CVSS 10.0): vm2 is an open source vm/sandbox for Node.js. Prior to version 3.11.4, NodeVM blocks several dangerous Node.js builtins…
CVE-2026-34208 — Critical (CVSS 10.0): SandboxJS is a JavaScript sandboxing library. Prior to 0.8.36, SandboxJS blocks direct assignment to global objects…
CVE-2026-34938 — Critical (CVSS 10.0): PraisonAI is a multi-agent teams system. Prior to version 1.5.90, execute_code() in praisonai-agents runs…
CVE-2026-2761 — Critical (CVSS 10.0): Sandbox escape in the Graphics: WebRender component. This vulnerability was fixed in Firefox 148, Firefox ESR 115.33,…
CVE-2022-32845 — Critical (CVSS 10.0): This issue was addressed with improved checks. This issue is fixed in watchOS 8.7, iOS 15.6 and iPadOS 15.6, macOS…
CVE-2026-45102 — Critical (CVSS 9.9): OneUptime is an open-source monitoring and observability platform. Prior to 10.0.98, OneUptime uses the Node.js' vm…

Browse all CWE-693 (Protection Mechanism Failure) vulnerabilities →