CVE-2026-20893VulnerabilityPublished 7 Jan 2026

CVE-2026-20893: Fujitsu Security Solution AuthConductor Client Basic V2 · Origin validation error

Affects Fujitsu Security Solution AuthConductor Client Basic V2Source CVE Database V5

Not known to be exploited · CVSS 7.8 High.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 3.0 base score

7.8High

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

EPSS: 0.1% chance of exploitation in 30 days – higher than 2% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

Attack Vector: Local
Attack Complexity: Low
Privileges Required: Low
User Interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: High
Availability: High

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

Attack Vector: Local: The vulnerable component is not bound to the network stack and the attacker’s path is via read/write/execute capabilities. Either: the attacker exploits the vulnerability by accessing the target system locally (e.g., keyboard, console), or remotely (e.g., SSH); or the attacker relies on User Interaction by another person to perform actions required to exploit the vulnerability (e.g., tricking a legitimate user into opening a malicious document).
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: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 7 Jan 2026
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

Affected software

Product	Affected	Fixed in
Fujitsu Client Computing LimitedFujitsu Security Solution AuthConductor Client Basic V2	Affected =2.0.25.0 and earlier	Fixed in–

AI-suggested

1. Monitor Fujitsu’s official channels for patches or updates addressing CVE-2026-20893 and apply them immediately upon release. 2. Until patches are available, restrict local user privileges to the minimum necessary to reduce the risk of exploitation by low-privileged users. 3. Implement strict access controls and monitoring on systems running AuthConductor Client Basic V2, including auditing registry changes and suspicious process executions. 4. Employ application whitelisting and endpoint detection and response (EDR) solutions to detect and block unauthorized code execution or privilege escalation attempts. 5. Educate system administrators and users about the risks of local privilege escalation vulnerabilities and enforce strong authentication and session management policies. 6. Consider isolating or limiting the use of affected Fujitsu security software on critical systems until a fix is applied. 7. Conduct regular vulnerability assessments and penetration testing focusing on local privilege escalation vectors to identify and remediate similar risks.

Description

CVE-2026-20893 is a high-severity origin validation vulnerability in Fujitsu Security Solution AuthConductor Client Basic V2 (version 2.0.25.0 and earlier). An attacker with login access to a Windows system running the affected software can exploit this flaw to execute arbitrary code with SYSTEM privileges and/or modify registry values. The vulnerability arises from improper origin validation, allowing privilege escalation without requiring user interaction. Although no known exploits are currently in the wild, the impact on confidentiality, integrity, and availability is significant. European organizations using this Fujitsu security product on Windows endpoints are at risk, especially in sectors relying on Fujitsu hardware and software. Mitigation involves promptly updating to a fixed version once available, restricting local user privileges, and monitoring registry changes. Countries with strong Fujitsu market presence and critical infrastructure using these solutions, such as Germany, the UK, and the Netherlands, are most likely to be affected.

Impact

For European organizations, the impact of CVE-2026-20893 is substantial. The ability for a local attacker to gain SYSTEM privileges means that any compromised user account could lead to full system takeover, including access to sensitive data, disruption of services, and the ability to install persistent malware or backdoors. This is particularly critical for industries with high security requirements such as finance, government, healthcare, and critical infrastructure. Since the vulnerability affects a security client software, exploitation could undermine the trustworthiness of authentication mechanisms and security controls. Organizations relying on Fujitsu hardware and software for endpoint security may face increased risk of insider threats or lateral movement by attackers who have gained initial access. The lack of known exploits in the wild currently reduces immediate risk but does not diminish the urgency for mitigation, as threat actors may develop exploits rapidly once the vulnerability is publicly known.

Summary

CVE-2026-20893 is a vulnerability identified in Fujitsu Security Solution AuthConductor Client Basic V2, specifically versions 2.0.25.0 and earlier. The root cause is an origin validation error within the software, which is designed to provide security functions on Windows systems. This flaw allows an attacker who already has login access to the affected Windows system to escalate privileges by executing arbitrary code with SYSTEM-level privileges, the highest level of access on Windows. Additionally, the attacker can modify critical Windows registry values, potentially altering system behavior or persistence mechanisms. The vulnerability does not require user interaction but does require the attacker to have some level of authenticated access (local privileges). The CVSS v3.0 score is 7.8, reflecting high severity due to the combination of local attack vector, low attack complexity, required privileges, and the impact on confidentiality, integrity, and availability. No public exploits are known at this time, but the potential for misuse is significant given the elevated privileges that can be gained. The vulnerability affects a security solution product from Fujitsu Client Computing Limited, which is used primarily in enterprise environments for authentication and security management. The lack of patch links suggests that a fix may not yet be publicly available, emphasizing the need for vigilance and interim mitigations.

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 14 Jan 2026, 16:01 UTC

Technical details

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