How severe is CVE-2021-3310?

CVE-2021-3310 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-3310 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (59th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-3310?

CVE-2021-3310 affects Westerndigital My Cloud Os. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-3310?

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-2021-3310 published?

CVE-2021-3310 was published on 2021-03-10 and last updated on 2026-06-17.

CVE-2021-3310

CVE-2021-3310 is a high-severity vulnerability in Westerndigital My Cloud Os 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. The underlying weakness is classified as CWE-59.

Key facts

Severity: High (CVSS 3.x base score 7.8)
CVSS v2: 4.6
EPSS exploit prediction: 1% (59th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-59
Affected product: Westerndigital My Cloud Os
Published: 2021-03-10
Last modified: 2026-06-17

Description

Western Digital My Cloud OS 5 devices before 5.10.122 mishandle Symbolic Link Following on SMB and AFP shares. This can lead to code execution and information disclosure (by reading local files).

Frequently asked questions

What is CVE-2021-3310?: Western Digital My Cloud OS 5 devices before 5.10.122 mishandle Symbolic Link Following on SMB and AFP shares. This can lead to code execution and information disclosure (by reading local files).
How severe is CVE-2021-3310?: CVE-2021-3310 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-3310 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (59th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-3310?: CVE-2021-3310 affects Westerndigital My Cloud Os. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-3310?: 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-2021-3310 published?: CVE-2021-3310 was published on 2021-03-10 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:o:westerndigital:my_cloud_os:*:*:*:*:*:*:*:*

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