How severe is CVE-2021-47961?

CVE-2021-47961 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability none.

Is CVE-2021-47961 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-2021-47961?

CVE-2021-47961 affects Synology Ssl Vpn Client. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-47961?

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.

Does CVE-2021-47961 have an EU (EUVD) identifier?

Yes. CVE-2021-47961 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2021-34779.

When was CVE-2021-47961 published?

CVE-2021-47961 was published on 2026-04-10 and last updated on 2026-06-17.

CVE-2021-47961

CVE-2021-47961 is a high-severity vulnerability in Synology Ssl Vpn Client with a CVSS 3.x base score of 8.1. 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-256.

Key facts

Severity: High (CVSS 3.x base score 8.1)
EPSS exploit prediction: 0% (24th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2021-34779
Weakness: CWE-256
Affected product: Synology Ssl Vpn Client
Published: 2026-04-10
Last modified: 2026-06-17

Description

A plaintext storage of a password vulnerability in Synology SSL VPN Client before 1.4.5-0684 allows remote attackers to access or influence the user's PIN code due to insecure storage. This may lead to unauthorized VPN configuration and potential interception of subsequent VPN traffic when combined with user interaction.

Frequently asked questions

What is CVE-2021-47961?: A plaintext storage of a password vulnerability in Synology SSL VPN Client before 1.4.5-0684 allows remote attackers to access or influence the user's PIN code due to insecure storage. This may lead to unauthorized VPN configuration and potential interception of subsequent VPN traffic when combined with user interaction.
How severe is CVE-2021-47961?: CVE-2021-47961 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2021-47961 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-2021-47961?: CVE-2021-47961 affects Synology Ssl Vpn Client. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-47961?: 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.
Does CVE-2021-47961 have an EU (EUVD) identifier?: Yes. CVE-2021-47961 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2021-34779.
When was CVE-2021-47961 published?: CVE-2021-47961 was published on 2026-04-10 and last updated on 2026-06-17.

References

https://www.synology.com/en-global/security/advisory/Synology_SA_26_05

Affected products (1)

cpe:2.3:a:synology:ssl_vpn_client:*:*:*:*:*:*:*:*

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