Description
GroupSession Free edition prior to ver5.3.0, GroupSession byCloud prior to ver5.3.3, and GroupSession ZION prior to ver5.3.2. do not validate origins in WebSockets. If a user accesses a crafted page, Chat information sent to the user may be exposed.
Affected products
groupsession: groupsession
References2
- groupsession.jp/info/info-news/security20251208 Vendor Advisory
- jvn.jp/en/jp/JVN19940619/ Third Party Advisory
Metrics
- CVSS 4.0
-
6.9
MEDIUM
Score source: CNA
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - EPSS — exploit probability
- 0% percentile: 4 · as of 11 November 2026
- CWE
- CWE-1385
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.