How severe is CVE-2021-29085?

CVE-2021-29085 has a CVSS 3.x base score of 8.6, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2021-29085 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (68th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-29085?

CVE-2021-29085 primarily affects Synology Diskstation Manager. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-29085?

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-2021-29085 published?

CVE-2021-29085 was published on 2021-06-23 and last updated on 2026-06-17.

CVE-2021-29085

CVE-2021-29085 is a high-severity vulnerability in Synology Diskstation Manager with a CVSS 3.x base score of 8.6. 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-74.

Key facts

Severity: High (CVSS 3.x base score 8.6)
CVSS v2: 5.0
EPSS exploit prediction: 1% (68th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-74
Affected product: Synology Diskstation Manager
Published: 2021-06-23
Last modified: 2026-06-17

Description

Improper neutralization of special elements in output used by a downstream component ('Injection') vulnerability in file sharing management component in Synology DiskStation Manager (DSM) before 6.2.3-25426-3 allows remote attackers to read arbitrary files via unspecified vectors.

Frequently asked questions

What is CVE-2021-29085?: Improper neutralization of special elements in output used by a downstream component ('Injection') vulnerability in file sharing management component in Synology DiskStation Manager (DSM) before 6.2.3-25426-3 allows remote attackers to read arbitrary files via unspecified vectors.
How severe is CVE-2021-29085?: CVE-2021-29085 has a CVSS 3.x base score of 8.6, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2021-29085 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (68th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-29085?: CVE-2021-29085 primarily affects Synology Diskstation Manager. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-29085?: 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-2021-29085 published?: CVE-2021-29085 was published on 2021-06-23 and last updated on 2026-06-17.

References

https://www.synology.com/security/advisory/Synology_SA_20_26

Affected products (2)

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

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