How severe is CVE-2021-29088?

CVE-2021-29088 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-2021-29088 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (24th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-29088?

CVE-2021-29088 affects Synology Diskstation Manager. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-29088?

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-2021-29088 published?

CVE-2021-29088 was published on 2021-06-01 and last updated on 2026-06-17.

CVE-2021-29088

CVE-2021-29088 is a high-severity vulnerability in Synology Diskstation Manager 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-22.

Key facts

Severity: High (CVSS 3.x base score 7.8)
CVSS v2: 4.6
EPSS exploit prediction: 0% (24th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-22
Affected product: Synology Diskstation Manager
Published: 2021-06-01
Last modified: 2026-06-17

Description

Improper limitation of a pathname to a restricted directory ('Path Traversal') in cgi component in Synology DiskStation Manager (DSM) before 6.2.4-25553 allows local users to execute arbitrary code via unspecified vectors.

Frequently asked questions

What is CVE-2021-29088?: Improper limitation of a pathname to a restricted directory ('Path Traversal') in cgi component in Synology DiskStation Manager (DSM) before 6.2.4-25553 allows local users to execute arbitrary code via unspecified vectors.
How severe is CVE-2021-29088?: CVE-2021-29088 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-2021-29088 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (24th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-29088?: CVE-2021-29088 affects Synology Diskstation Manager. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-29088?: 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-2021-29088 published?: CVE-2021-29088 was published on 2021-06-01 and last updated on 2026-06-17.

References

https://www.synology.com/security/advisory/Synology_SA_21_03

Affected products (1)

cpe:2.3:o:synology:diskstation_manager:*:*:*:*:*:*:*:*

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