CVE-2025-59923VulnerabilityPublished 9 Dec 2025Updated 14 Jan 2026

CVE-2025-59923: Fortinet FortiAuthenticator · Escalation of privilege

Affects Fortinet FortiAuthenticatorSource CVE Database V5

Not known to be exploited · CVSS 2.6 Low.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 3.1 base score

2.6Low

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

EPSS: 0.2% chance of exploitation in 30 days – higher than 11% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:N/A:N/E:P/RL:U/RC:C

Base metrics

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

Temporal metrics

Exploit Code Maturity: Proof-of-Concept
Remediation Level: Unavailable
Report Confidence: Confirmed

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: High: The attacker is authorized with (i.e., requires) privileges that provide significant (e.g., administrative) control over the vulnerable component that could affect component-wide settings and files.
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: 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: None: There is no loss of integrity within the impacted component.
Availability: None: There is no impact to availability within the impacted component.
Exploit Code Maturity: Proof-of-Concept: Proof-of-concept exploit code is available, or an attack demonstration is not practical for most systems. The code or technique is not functional in all situations and may require substantial modification by a skilled attacker.
Remediation Level: Unavailable: There is either no solution available or it is impossible to apply.
Report Confidence: Confirmed: Detailed reports exist, or functional reproduction is possible (functional exploits may provide this). Source code is available to independently verify the assertions of the research, or the author or vendor of the affected code has confirmed the presence of the vulnerability.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 9 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

Affected software

Product	Affected	Fixed in
Fortinet FortiAuthenticator	Affected =6.6.0 =6.5.0 =6.4.0	Fixed in–

AI-suggested

1. Restrict administrative access strictly to trusted personnel and minimize the number of users with read-only admin privileges. 2. Implement strong authentication mechanisms for all administrators, including multi-factor authentication, to reduce the risk of credential compromise. 3. Monitor administrative access logs and alert on unusual or suspicious activity, especially attempts to access messaging service credentials. 4. Segregate duties so that read-only admin roles do not have access to sensitive credential information where possible. 5. Apply Fortinet patches promptly once released to remediate the vulnerability. 6. Conduct regular audits of FortiAuthenticator configurations and permissions to ensure adherence to the principle of least privilege. 7. Consider network segmentation to limit access to FortiAuthenticator management interfaces. 8. Educate administrators about the risks of credential exposure and encourage secure handling of credentials. 9. If immediate patching is not possible, implement compensating controls such as enhanced monitoring and temporary restriction of read-only admin capabilities related to messaging services.

Description

An improper access control vulnerability in Fortinet FortiAuthenticator 6.6.0 through 6.6.6, FortiAuthenticator 6.5 all versions, FortiAuthenticator 6.4 all versions, FortiAuthenticator 6.3 all versions may allow an authenticated attacker with at least read-only admin permission to obtain the credentials of other administrators' messaging services via crafted requests.

Impact

For European organizations, the primary impact is the potential unauthorized disclosure of administrator messaging service credentials, which could facilitate lateral movement or privilege escalation within the network. While the vulnerability requires authenticated access with read-only admin rights, such access might be obtained through compromised credentials or insider threats. Organizations relying on FortiAuthenticator for identity and access management, especially those integrating messaging services for alerts or multi-factor authentication, could see increased risk of credential theft leading to broader security incidents. The impact on confidentiality could undermine trust in authentication systems and potentially expose sensitive internal communications. However, since the vulnerability does not affect system integrity or availability, direct disruption of services is unlikely. The low CVSS score suggests limited immediate risk, but the sensitivity of the credentials involved warrants attention, particularly in sectors with stringent compliance requirements such as finance, healthcare, and government.

References

fortiguard.fortinet.com/psirt/FG-IR-25-616 (opens in a new tab)

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 14 Jan 2026, 15:03 UTC

Technical details

References

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