CVE-2025-61950VulnerabilityPublished 12 Dec 2025

CVE-2025-61950: Japan Total System GroupSession Free edition · Insecure Direct Object Reference

Affects Japan Total System GroupSession Free editionSource CVE Database V5

Not known to be exploited · CVSS 4.3 Medium : upgrade to 5.3.0 when convenient.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 3.0 base score

4.3Medium

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 5.3.0

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: Low
User Interaction: None
Scope: Unchanged
Confidentiality: None
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: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within 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 2026-10-25.

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 5.3.0.

Affected software

Product	Affected	Fixed in
Japan Total System Co.,Ltd. GroupSession Free edition	Affected <5.3.0	Fixed in 5.3.0

AI-suggested

1. 2. If you cannot patch yet, restrict user privileges to the minimum necessary, especially limiting the ability to create or modify Circular notices. 3. Implement monitoring and logging of changes to Circular notices and memo fields to detect unauthorized modifications promptly. 4. Conduct regular audits of user permissions and access controls within GroupSession to ensure only authorized personnel can perform sensitive actions. 5. Educate users about the risk of unauthorized data modification and encourage reporting of suspicious activity. 6. Coordinate with the vendor for timely security updates and advisories. 7. Consider network segmentation or additional access controls to limit exposure of GroupSession servers to untrusted networks. 8. Review and enhance incident response plans to address potential integrity breaches in collaboration platforms.

Description

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.

Impact

For European organizations, this vulnerability could undermine the integrity of internal communications and document workflows managed through GroupSession products. Unauthorized modification of Circular notices' memo fields may lead to misinformation, miscommunication, or manipulation of official records, potentially affecting decision-making processes and compliance with regulatory requirements. While the vulnerability does not expose sensitive data or disrupt service availability, the integrity compromise could damage organizational trust and operational reliability. Sectors such as government agencies, healthcare, finance, and large enterprises that utilize GroupSession for collaboration and document circulation are particularly at risk. The medium severity rating indicates that while the threat is not critical, it should not be overlooked, especially in environments where data integrity is paramount. The absence of known exploits reduces immediate risk but does not preclude future exploitation attempts. Organizations failing to update may face targeted attacks exploiting this flaw to alter official communications or internal notices.

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

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