What is CVE-2017-2166?

CVE-2017-2166 is a medium-severity vulnerability in Groupsession, classified under URL Redirection to Untrusted Site (Open Redirect). CVSS score: 6.1/10. Published 2018-01-26.

How severe is CVE-2017-2166?

Medium severity. CVSS v3 base score is 6.1 out of 10.

Open Redirect in Groupsession

CVE-2017-2166

Open redirect vulnerability in GroupSession version 4.7.0 and earlier allows an attacker to redirect users to arbitrary web sites and conduct phishing attacks via unspecified vectors.

Vulnerability class: Open Redirect

Published 2018-01-26 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.008 (53.8th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 54th percentile — 53.8% 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

Groupsession
Japan Total System Co.,ltd. Groupsession — versions version 4.7.0 and earlier

Weakness classification (CWE)

CWE-601 — URL Redirection to Untrusted Site (Open Redirect)

References

jvn.jp/en/jp/JVN26200083/index.html (VDB Entry, Third Party Advisory, third-party-advisory)

Frequently asked questions

What is CVE-2017-2166?: CVE-2017-2166 is a medium-severity vulnerability in Groupsession, classified under URL Redirection to Untrusted Site (Open Redirect). CVSS score: 6.1/10. Published 2018-01-26.
How severe is CVE-2017-2166?: Medium severity. CVSS v3 base score is 6.1 out of 10.