VulnerabilityPublished 9 Dec 2025

CVE-2025-40806: Siemens Gridscale X Prepay · Observable Response Discrepancy

Affects Siemens Gridscale X PrepaySource CVE Database V5

Not known to be exploited · CVSS 5.3 Medium.

Data as of 26 Oct 2026, 10:12 UTC

CVSS 3.1 base score

5.3Medium

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

EPSS: 0.4% chance of exploitation in 30 days – higher than 39% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

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

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 26 Oct 2026.

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 or the CVSS exploit maturity 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
Siemens Gridscale X Prepay	Affected =0	Fixed in–

AI-suggested

European organizations should implement a multi-layered approach to mitigate this vulnerability beyond waiting for Siemens patches. First, monitor authentication logs for unusual login attempts and implement alerting for repeated failed logins or suspicious patterns indicative of brute force attacks. Second, enforce strong account lockout policies that temporarily disable accounts after a defined number of failed login attempts to slow down brute force efforts. Third, deploy multi-factor authentication (MFA) wherever possible to reduce the risk of account compromise even if credentials are guessed. Fourth, consider implementing web application firewalls (WAFs) or intrusion prevention systems (IPS) with rules to detect and block user enumeration and brute force attack patterns targeting Gridscale X Prepay interfaces. Fifth, conduct regular user account audits to disable or remove inactive or unnecessary accounts, reducing the attack surface. Finally, maintain close communication with Siemens for timely patch releases and apply updates promptly once available. Network segmentation and limiting access to the Gridscale X Prepay management interfaces to trusted IP ranges can further reduce exposure.

Description

A vulnerability has been identified in Gridscale X Prepay (All versions < V4.2.1). The affected application is vulnerable to user enumeration due to distinguishable responses. This could allow an unauthenticated remote attacker to determine if a user is valid or not, enabling a brute force attack with valid users.

Impact

For European organizations, especially those in critical infrastructure sectors such as energy and industrial automation where Siemens products are prevalent, this vulnerability poses a risk of user enumeration that can lead to brute force attacks. Successful brute force attacks could result in unauthorized access to user accounts, potentially enabling further lateral movement or privilege escalation if weak or reused credentials are present. While the vulnerability itself does not directly compromise system integrity or availability, it lowers the barrier for attackers to identify valid accounts and attempt credential stuffing or password guessing attacks. This can increase the likelihood of account compromise, data exposure, or unauthorized operational control. Given Siemens' strong presence in countries like Germany, France, and the UK, organizations in these regions are at higher risk. The vulnerability could also affect supply chain partners and service providers using Gridscale X Prepay, amplifying the potential impact. The medium severity rating reflects the moderate risk posed, but the strategic importance of affected systems in European critical infrastructure elevates the need for prompt mitigation.

CWE-204Observable Response Discrepancy (opens in a new tab)
Base weakness
The product provides different responses to incoming requests in a way that reveals internal state information to an unauthorized actor outside of the intended control sphere.
Architecture and Design · Separation of Privilege
Compartmentalize the system to have "safe" areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area.
Implementation
Ensure that error messages only contain minimal details that are useful to the intended audience and no one else. The messages need to strike the balance between being too cryptic (which can confuse users) or being too detailed (which may reveal more than intended).
OWASP Cheat Sheets
Error Handling (opens in a new tab)
Logging (opens in a new tab)
OWASP ASVS 4.0.3
V8.3.4 (opens in a new tab)
V14.3.3 (opens in a new tab)
V7.3.3 (opens in a new tab)
Attack patterns
ICMP IP Total Length Field Probe (opens in a new tab)
ICMP IP 'ID' Field Error Message Probe (opens in a new tab)
Application Fingerprinting (opens in a new tab)
System Footprinting (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

cert-portal.siemens.com/productcert/html/ssa-356310.html (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 16 Dec 2025, 11:38 UTC

WeaknessesCWE-204

Technical details

References

Community reviews

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