How severe is CVE-2021-20631?

CVE-2021-20631 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.

Is CVE-2021-20631 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (50th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-20631?

CVE-2021-20631 affects Cybozu Office. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-20631?

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

When was CVE-2021-20631 published?

CVE-2021-20631 was published on 2021-03-18 and last updated on 2026-06-17.

CVE-2021-20631

CVE-2021-20631 is a medium-severity vulnerability in Cybozu Office with a CVSS 3.x base score of 6.5. 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-20.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
CVSS v2: 4.0
EPSS exploit prediction: 1% (50th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-20
Affected product: Cybozu Office
Published: 2021-03-18
Last modified: 2026-06-17

Description

Improper input validation vulnerability in Custom App of Cybozu Office 10.0.0 to 10.8.4 allows authenticated attacker to alter the data of Custom App via unspecified vectors.

Frequently asked questions

What is CVE-2021-20631?: Improper input validation vulnerability in Custom App of Cybozu Office 10.0.0 to 10.8.4 allows authenticated attacker to alter the data of Custom App via unspecified vectors.
How severe is CVE-2021-20631?: CVE-2021-20631 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.
Is CVE-2021-20631 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (50th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-20631?: CVE-2021-20631 affects Cybozu Office. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-20631?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-20631 published?: CVE-2021-20631 was published on 2021-03-18 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:cybozu:office:*:*:*:*:*:*:*:*

More vulnerabilities in Cybozu Office

CVE-2014-5314 — Critical (CVSS 9.0): Buffer overflow in Cybozu Office 9 and 10 before 10.1.0, Mailwise 4 and 5 before 5.1.4, and Dezie 8 before 8.1.1 allows…
CVE-2016-1151 — High (CVSS 8.8): Multiple cross-site request forgery (CSRF) vulnerabilities in Cybozu Office 9.9.0 through 10.3.0 allow remote attackers…
CVE-2018-0704 — High (CVSS 7.5): Directory traversal vulnerability in Cybozu Office 10.0.0 to 10.8.1 allows remote attackers to delete arbitrary files…
CVE-2018-0703 — High (CVSS 7.5): Directory traversal vulnerability in Cybozu Office 10.0.0 to 10.8.1 allows remote attackers to delete arbitrary files…
CVE-2015-8483 — High (CVSS 7.4): Open redirect vulnerability in Cybozu Office 10.2.0 through 10.3.0 allows remote attackers to redirect users to…
CVE-2024-39817 — Medium (CVSS 6.5): Insertion of sensitive information into sent data issue exists in Cybozu Office 10.0.0 to 10.8.6, which may allow a…

All CVEs affecting Cybozu Office →

Other CWE-20 (Improper Input Validation) vulnerabilities

CVE-2026-48316 — Critical (CVSS 10.0): ColdFusion versions 2025.9, 2023.20 and earlier are affected by an Improper Input Validation vulnerability that could…
CVE-2026-48281 — Critical (CVSS 10.0): ColdFusion versions 2025.9, 2023.20 and earlier are affected by an Improper Input Validation vulnerability that could…
CVE-2026-48277 — Critical (CVSS 10.0): ColdFusion versions 2025.9, 2023.20 and earlier are affected by an Improper Input Validation vulnerability that could…
CVE-2026-48055 — Critical (CVSS 10.0): Streambert is a cross-platform Electron Desktop App to stream and download any video media. In versions 2.4.0 and…
CVE-2026-34910 — Critical (CVSS 10.0): A malicious actor with access to the network could exploit an Improper Input Validation vulnerability found in UniFi OS…
CVE-2026-33587 — Critical (CVSS 10.0): Lack of user input sanitisation in Open Notebook v1.8.3 allows the application user to execute Python code (and…

Browse all CWE-20 (Improper Input Validation) vulnerabilities →