Auth bypass in Groupsession
CVE-2025-61950
In GroupSession, a Circular notice can be created with its memo field non-editable, but the authorization check is improperly implemented. With some crafted request, a logged-in user may alter the memo field. The affected products and versions are GroupSession Free edition prior to ver5.3.0, GroupSession byCloud prior to ver5.3.3, and GroupSession ZION prior to ver5.3.2.
Vulnerability class: IDOR (Insecure Direct Object Reference)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N.
EPSS exploit prediction
EPSS: 0.002 (7.6th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 8th percentile — 7.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: +0.000
Affected products
- Groupsession
- Japan Total System Co.,ltd. Groupsession Bycloud — versions prior to ver5.3.3
- Japan Total System Co.,ltd. Groupsession Free Edition — versions prior to ver5.3.0
- Japan Total System Co.,ltd. Groupsession Zion — versions prior to ver5.3.2
Weakness classification (CWE)
References
- groupsession.jp/info/info-news/security20251208 (Vendor Advisory)
- jvn.jp/en/jp/JVN19940619/ (Third Party Advisory)
Frequently asked questions
- What is CVE-2025-61950?
- CVE-2025-61950 is a medium-severity vulnerability in Groupsession, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 4.3/10. Published 2025-12-12.
- How severe is CVE-2025-61950?
- Medium severity. CVSS v3 base score is 4.3 out of 10.