How severe is CVE-2021-34518?

CVE-2021-34518 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-34518 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (80th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-34518?

CVE-2021-34518 primarily affects Microsoft Excel. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-34518?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-34518 published?

CVE-2021-34518 was published on 2021-07-14 and last updated on 2026-06-17.

CVE-2021-34518

CVE-2021-34518 is a high-severity vulnerability in Microsoft Excel with a CVSS 3.x base score of 7.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: High (CVSS 3.x base score 7.8)
CVSS v2: 6.8
EPSS exploit prediction: 2% (80th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Microsoft Excel
Published: 2021-07-14
Last modified: 2026-06-17

Description

Microsoft Excel Remote Code Execution Vulnerability

Frequently asked questions

What is CVE-2021-34518?: Microsoft Excel Remote Code Execution Vulnerability
How severe is CVE-2021-34518?: CVE-2021-34518 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-34518 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (80th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-34518?: CVE-2021-34518 primarily affects Microsoft Excel. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-34518?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-34518 published?: CVE-2021-34518 was published on 2021-07-14 and last updated on 2026-06-17.

References

https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-34518

Affected products (6)

cpe:2.3:a:microsoft:excel:2013:sp1:*:*:*:*:x64:*
cpe:2.3:a:microsoft:excel:2013:sp1:*:*:*:*:x86:*
cpe:2.3:a:microsoft:excel:2013:sp1:*:*:rt:*:*:*
cpe:2.3:a:microsoft:excel:2016:*:*:*:*:*:x64:*
cpe:2.3:a:microsoft:excel:2016:*:*:*:*:*:x86:*
cpe:2.3:a:microsoft:office_web_apps_server:2013:sp1:*:*:*:*:*:*

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