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.
Conclusion & alert: CVE-2025-61987 is rated Low Risk (29/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.14%). Mandatory action: Monitor for updates and reassess as exploit intelligence or EPSS changes.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2026-06-15 | 0.01% | 0.14% | +0.12% |
| 2 | 2025-12-12 | — | 0.01% | — |
Full EPSS history (2 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 6.9 | 4.0 | MEDIUM |
|
— | — | [email protected] |
| 5.3 | 3.0 | MEDIUM |
|
3.9 | 1.4 | [email protected] |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| groupsession | groupsession | < 5.3.0 | cpe:2.3:a:groupsession:groupsession:*:*:*:*:free:*:*:* |
| groupsession | groupsession | < 5.3.2 | cpe:2.3:a:groupsession:groupsession:*:*:*:*:zion:*:*:* |
| groupsession | groupsession | < 5.3.3 | cpe:2.3:a:groupsession:groupsession:*:*:*:*:bycloud:*:*:* |
| URL | Tags |
|---|---|
| https://groupsession.jp/info/info-news/security20251208 | Vendor Advisory |
| https://jvn.jp/en/jp/JVN19940619/ | Third Party Advisory |