CVE-2021-40454

CVE-2021-40454 is a medium-severity vulnerability in Microsoft 365 Apps with a CVSS 3.x base score of 5.5. 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-312.

Key facts

• Severity: Medium (CVSS 3.x base score 5.5)
• CVSS v2: 2.1
• EPSS exploit prediction: 0% (38th percentile)
• Actively exploited: Not listed in CISA KEV
• Weakness: CWE-312
• Affected product: Microsoft 365 Apps
• Published: 2021-10-13
• Last modified: 2026-06-17

Description

Rich Text Edit Control Information Disclosure Vulnerability

Frequently asked questions

What is CVE-2021-40454?

Rich Text Edit Control Information Disclosure Vulnerability

How severe is CVE-2021-40454?

CVE-2021-40454 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2021-40454 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (38th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-40454?

CVE-2021-40454 primarily affects Microsoft 365 Apps. In total, 44 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-40454?

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

When was CVE-2021-40454 published?

CVE-2021-40454 was published on 2021-10-13 and last updated on 2026-06-17.

References

• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-40454

Affected products (44)

• cpe:2.3:a:microsoft:365_apps:-:*:*:*:enterprise:*:x64:*
• cpe:2.3:a:microsoft:365_apps:-:*:*:*:enterprise:*:x86:*
• cpe:2.3:a:microsoft:office:2013:sp1:*:*:*:*:x64:*
• cpe:2.3:a:microsoft:office:2013:sp1:*:*:*:*:x86:*
• cpe:2.3:a:microsoft:office:2013_rt:sp1:*:*:*:*:*:*
• cpe:2.3:a:microsoft:office:2016:*:*:*:*:*:x64:*
• cpe:2.3:a:microsoft:office:2016:*:*:*:*:*:x86:*
• cpe:2.3:a:microsoft:office:2019:*:*:*:*:*:x64:*
• cpe:2.3:a:microsoft:office:2019:*:*:*:*:*:x86:*
• cpe:2.3:a:microsoft:office:2019:*:*:*:*:macos:*:*
• cpe:2.3:a:microsoft:office:2021:*:ltsc:*:*:macos:*:*
• cpe:2.3:a:microsoft:office:2021:*:ltsc:*:*:x64:*:*
• cpe:2.3:a:microsoft:office:2021:*:ltsc:*:*:x86:*:*
• cpe:2.3:o:microsoft:windows_10:-:*:*:*:*:*:x64:*
• cpe:2.3:o:microsoft:windows_10:-:*:*:*:*:*:x86:*
• cpe:2.3:o:microsoft:windows_10:20h2:*:*:*:*:*:arm64:*
• cpe:2.3:o:microsoft:windows_10:20h2:*:*:*:*:*:x64:*
• cpe:2.3:o:microsoft:windows_10:20h2:*:*:*:*:*:x86:*
• cpe:2.3:o:microsoft:windows_10:21h1:*:*:*:*:*:arm64:*
• cpe:2.3:o:microsoft:windows_10:21h1:*:*:*:*:*:x64:*
• cpe:2.3:o:microsoft:windows_10:21h1:*:*:*:*:*:x86:*
• cpe:2.3:o:microsoft:windows_10:1607:*:*:*:*:*:x64:*
• cpe:2.3:o:microsoft:windows_10:1607:*:*:*:*:*:x86:*
• cpe:2.3:o:microsoft:windows_10:1809:*:*:*:*:*:arm64:*
• cpe:2.3:o:microsoft:windows_10:1809:*:*:*:*:*:x64:*
• cpe:2.3:o:microsoft:windows_10:1809:*:*:*:*:*:x86:*
• cpe:2.3:o:microsoft:windows_10:1909:*:*:*:*:*:arm64:*
• cpe:2.3:o:microsoft:windows_10:1909:*:*:*:*:*:x64:*
• cpe:2.3:o:microsoft:windows_10:1909:*:*:*:*:*:x86:*
• cpe:2.3:o:microsoft:windows_10:2004:*:*:*:*:*:arm64:*
• cpe:2.3:o:microsoft:windows_10:2004:*:*:*:*:*:x64:*
• cpe:2.3:o:microsoft:windows_10:2004:*:*:*:*:*:x86:*
• cpe:2.3:o:microsoft:windows_11:-:*:*:*:*:*:arm64:*
• cpe:2.3:o:microsoft:windows_11:-:*:*:*:*:*:x64:*
• cpe:2.3:o:microsoft:windows_8.1:-:*:*:*:*:*:x64:*
• cpe:2.3:o:microsoft:windows_8.1:-:*:*:*:*:*:x86:*
• cpe:2.3:o:microsoft:windows_rt_8.1:-:*:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows_server:20h2:*:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows_server:2004:*:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows_server_2012:-:*:*:*:*:*:*:*

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-312 (Cleartext Storage of Sensitive Information) vulnerabilities

• CVE-2022-43757 — Critical (CVSS 9.9): A Cleartext Storage of Sensitive Information vulnerability in SUSE Rancher allows users on managed clusters to gain…
• CVE-2021-36782 — Critical (CVSS 9.9): A Cleartext Storage of Sensitive Information vulnerability in SUSE Rancher allows authenticated Cluster Owners, Cluster…
• CVE-2020-9045 — Critical (CVSS 9.9): During installation or upgrade to Software House C•CURE 9000 v2.70 and American Dynamics victor Video Management…
• CVE-2026-31848 — Critical (CVSS 9.8): Nexxt Solutions Nebula 300+ firmware through version 12.01.01.37 uses the ecos_pw cookie for authentication, which…
• CVE-2025-65826 — Critical (CVSS 9.8): The mobile application was found to contain stored credentials for the network it was developed on. If an attacker…
• CVE-2025-34206 — Critical (CVSS 9.8): Vasion Print (formerly PrinterLogic) Virtual Appliance Host and Application (VA and SaaS deployments) mount host…

Browse all CWE-312 (Cleartext Storage of Sensitive Information) vulnerabilities →