CVE-2025-65120VulnerabilityPublished 12 Dec 2025

CVE-2025-65120: Japan Total System GroupSession Free edition · Cross-site scripting (XSS)

Affects Japan Total System GroupSession Free editionSource CVE Database V5

Not known to be exploited · CVSS 6.1 Medium : upgrade to 5.7.1 when convenient.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 3.0 base score

6.1Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.1% chance of exploitation in 30 days – higher than 8% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 5.7.1

CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: Required
Scope: Changed
Confidentiality: Low
Integrity: Low
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
Confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 12 Dec 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-26.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade Japan Total System GroupSession Free edition to 5.7.1.

Affected software

Product	Affected	Fixed in
Japan Total System Co.,Ltd. GroupSession Free edition	Affected <5.7.1	Fixed in 5.7.1

AI-suggested

The primary mitigation is to upgrade all affected GroupSession installations to version 5.7.1 or later, where the vulnerability has been addressed. In the absence of immediate upgrade capability, organizations should implement strict input validation and output encoding on all user-supplied data to prevent script injection. Deploying Content Security Policy (CSP) headers can help restrict the execution of unauthorized scripts. Additionally, organizations should educate users about the risks of clicking on suspicious links and implement email filtering to reduce phishing attempts. Monitoring web server logs for unusual URL patterns or repeated attempts to exploit XSS can aid early detection. Network segmentation and limiting access to GroupSession interfaces to trusted IP ranges can reduce exposure. Finally, regular security assessments and penetration testing focused on web application security should be conducted to identify and remediate similar vulnerabilities proactively.

Description

Reflected cross-site scripting vulnerability exists in GroupSession Free edition prior to ver5.7.1, GroupSession byCloud prior to ver5.7.1, and GroupSession ZION prior to ver5.7.1. If a user accesses a crafted page or URL, an arbitrary script may be executed on the web browser of the user.

Impact

For European organizations using GroupSession products, this vulnerability poses a risk to the confidentiality and integrity of sensitive information exchanged via the platform. Attackers exploiting this XSS flaw could steal session cookies or authentication tokens, enabling unauthorized access to user accounts and potentially sensitive corporate data. This could lead to data breaches, unauthorized data manipulation, or lateral movement within the network if the compromised accounts have elevated privileges. The reflected XSS nature requires user interaction, so phishing or social engineering campaigns may be used to lure victims. The impact is particularly significant for organizations with external-facing GroupSession portals accessible by partners, clients, or remote employees. Disruption of trust and potential regulatory consequences under GDPR could arise if personal or sensitive data is exposed. However, availability is not impacted, and no known exploits are currently active in the wild, which somewhat limits immediate risk.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 19 Dec 2025, 08:33 UTC

Technical details

References

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