How severe is CVE-2017-15891?

CVE-2017-15891 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.

Is CVE-2017-15891 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (61st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2017-15891?

CVE-2017-15891 affects Synology Calendar. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2017-15891?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2017-15891 published?

CVE-2017-15891 was published on 2017-12-08 and last updated on 2026-06-17.

CVE-2017-15891

CVE-2017-15891 is a medium-severity vulnerability in Synology Calendar with a CVSS 3.x base score of 6.5. 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-284.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
CVSS v2: 4.0
EPSS exploit prediction: 1% (61st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-284
Affected product: Synology Calendar
Published: 2017-12-08
Last modified: 2026-06-17

Description

Improper access control vulnerability in SYNO.Cal.EventBase in Synology Calendar before 2.0.1-0242 allows remote authenticated users to modify calendar event via unspecified vectors.

Frequently asked questions

What is CVE-2017-15891?: Improper access control vulnerability in SYNO.Cal.EventBase in Synology Calendar before 2.0.1-0242 allows remote authenticated users to modify calendar event via unspecified vectors.
How severe is CVE-2017-15891?: CVE-2017-15891 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.
Is CVE-2017-15891 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (61st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2017-15891?: CVE-2017-15891 affects Synology Calendar. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2017-15891?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2017-15891 published?: CVE-2017-15891 was published on 2017-12-08 and last updated on 2026-06-17.

References

https://www.synology.com/en-global/support/security/Synology_SA_17_68_Calendar

Affected products (1)

cpe:2.3:a:synology:calendar:*:*:*:*:*:*:*:*

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