What is CVE-2018-8917?

CVE-2018-8917 is a medium-severity vulnerability in Synology Diskstation Manager, classified under Cross-site Scripting. CVSS score: 6.5/10. Published 2018-12-24.

How severe is CVE-2018-8917?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Is CVE-2018-8917 known to be exploited?

2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

XSS in Synology Diskstation Manager

CVE-2018-8917

Cross-site scripting (XSS) vulnerability in info.cgi in Synology DiskStation Manager (DSM) before 6.1.6-15266 allows remote attackers to inject arbitrary web script or HTML via the host parameter.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2018-12-24 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:L.

EPSS exploit prediction

EPSS: 0.008 (54.9th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 55th percentile — 54.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.008 · newest: 0.008 · change: 0.000

Affected products

Synology Diskstation Manager
Synology Diskstation Manager (Dsm) — versions unspecified

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

Public proof-of-concept exploits

References

www.synology.com/security/advisory/Synology_SA_18_14 (Vendor Advisory)

Frequently asked questions

What is CVE-2018-8917?: CVE-2018-8917 is a medium-severity vulnerability in Synology Diskstation Manager, classified under Cross-site Scripting. CVSS score: 6.5/10. Published 2018-12-24.
How severe is CVE-2018-8917?: Medium severity. CVSS v3 base score is 6.5 out of 10.
Is CVE-2018-8917 known to be exploited?: 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.