How severe is CVE-2020-27659?

CVE-2020-27659 has a CVSS 3.x base score of 8.4, rated high severity. It is exploitable over network with low attack complexity, requires high privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2020-27659 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 5% (91st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-27659?

CVE-2020-27659 affects Synology Safeaccess. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-27659?

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-2020-27659 published?

CVE-2020-27659 was published on 2020-11-30 and last updated on 2026-06-17.

CVE-2020-27659

CVE-2020-27659 is a high-severity vulnerability in Synology Safeaccess with a CVSS 3.x base score of 8.4. 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-79.

Key facts

Severity: High (CVSS 3.x base score 8.4)
CVSS v2: 3.5
EPSS exploit prediction: 5% (91st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Synology Safeaccess
Published: 2020-11-30
Last modified: 2026-06-17

Description

Multiple cross-site scripting (XSS) vulnerabilities in Synology SafeAccess before 1.2.3-0234 allow remote attackers to inject arbitrary web script or HTML via the (1) domain or (2) profile parameter.

Frequently asked questions

What is CVE-2020-27659?: Multiple cross-site scripting (XSS) vulnerabilities in Synology SafeAccess before 1.2.3-0234 allow remote attackers to inject arbitrary web script or HTML via the (1) domain or (2) profile parameter.
How severe is CVE-2020-27659?: CVE-2020-27659 has a CVSS 3.x base score of 8.4, rated high severity. It is exploitable over network with low attack complexity, requires high privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2020-27659 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 5% (91st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-27659?: CVE-2020-27659 affects Synology Safeaccess. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-27659?: 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-2020-27659 published?: CVE-2020-27659 was published on 2020-11-30 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:synology:safeaccess:*:*:*:*:*:*:*:*

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