CVE-2025-40805

CRITICAL

Affected devices do not properly enforce user authentication on specific API endpoints. This could facilitate an unauthenticated remote attacker to circumvent authentication and impersonate a legit...

Affects 0 products across 1 vendor.

BCS7.0
CVSS 3.110.0
CVSS v410.0
EPSS0.6%
Percentile45th
PatchUnknown
CVSS Vector — Plain English Remotely exploitable over the network, low complexity, no authentication required, no user interaction needed, can impact systems beyond the vulnerable component, full confidentiality impact, full integrity impact, full availability impact.
CWE Weakness Definitions
CWE-639: Authorization Bypass Through User-Controlled Key (IDOR)

Software uses a user-supplied key to access resources without verifying authorization for that specific resource.

◆ SAGE Intelligence — CITED Relevance Research Team

CVE-2025-40805 affects Fujitsu-Siemens and Siemens devices, allowing unauthenticated remote attackers to circumvent authentication and impersonate legitimate users. The vulnerability has a CVSS score of 10.0, indicating critical severity. Immediate action is required to mitigate potential risks to operational integrity and security.

BSID: BS-2026-GLOBAL-277275-C • Model: Qwen/Qwen2.5-72B-Instruct-AWQ • Confidence: HIGH

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Frequently Asked Questions
What is CVE-2025-40805?
CVE-2025-40805 affects Fujitsu-Siemens and Siemens devices, allowing unauthenticated remote attackers to circumvent authentication and impersonate legitimate users. The vulnerability has a CVSS score of 10.0, indicating critical severity. Immediate action is required to mitigate potential risks to operational integrity and security.
What is the CVSS score for CVE-2025-40805?
CVE-2025-40805 has CVSS 10.0 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H. EPSS: 0.6%.
Is CVE-2025-40805 actively exploited?
No confirmed active exploitation of CVE-2025-40805 as of 2026-05-30.
How do I remediate CVE-2025-40805?
Priority: IMMEDIATE.
What systems are affected by CVE-2025-40805?
CVE-2025-40805 affects: Siemens.
What NERC-CIP standard applies to CVE-2025-40805?
NERC CIP CIP-007 CIP-007-R2: This CVE violates CIP-007-R2 by failing to ensure that electronic access to BES Cyber Systems is controlled and monitored, which is essential for maintaining the security and reliability of the power grid.
What IEC 62443 requirement maps to CVE-2025-40805?
IEC 62443 SR 7.6: This CVE maps to SR 7.6, which requires that access to system functions and data is restricted to authorized individuals. The lack of proper authentication enforcement directly contravenes this requirement, posing a significant risk to system security.
Vulnerability Details
CVE IDCVE-2025-40805
BSIDBS-2026-GLOBAL-277275-C BreachSpider Global ID
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Published2026-01-13
Last Modified2026-04-15
ICS Relevance55%
Weakness (CWE)
Verticals
ICS-OT
SourceNVD
Official Description

Affected devices do not properly enforce user authentication on specific API endpoints. This could facilitate an unauthenticated remote attacker to circumvent authentication and impersonate a legitimate user. Successful exploitation requires that the attacker has learned the identity of a legitimate user.

Source: NIST NVD / MITRE CVE Database

Attack Vector Analysis — CITED Relevance

The vulnerability arises from improper enforcement of user authentication on specific API endpoints. An unauthenticated remote attacker can exploit this issue to bypass authentication mechanisms and gain unauthorized access to the system, potentially leading to full control over the affected device.

Exploitation Likelihood: MEDIUM

Affected Products
VendorProductFixed Version
Siemens —
Remediation

No patch URL on record. Monitor vendor security advisories directly.

Threat Intelligence
● Threat Intelligence Validated: August 2026 | Threat Age: 200 Days
CISA KEVNot in KEV catalog
Public ExploitNot confirmed
PoC CodeNot confirmed
● Virtual Patch — CITED Relevance SAGE Engine MEDIUM CONFIDENCE

Implement strict access controls and monitor API endpoint usage for unusual activity. Consider deploying a web application firewall (WAF) to filter and block suspicious requests.

No reliable network detection signature exists for this vulnerability class — apply the compensating controls above and the vendor patch. SAGE only publishes a network rule when a concrete on-the-wire signature can be grounded in the advisory.

NERC CIP: CIP-007 CIP-007-R2
This CVE violates CIP-007-R2 by failing to ensure that electronic access to BES Cyber Systems is controlled and monitored, which is essential for maintaining the security and reliability of the power grid.
IEC 62443: SR 7.6
This CVE maps to SR 7.6, which requires that access to system functions and data is restricted to authorized individuals. The lack of proper authentication enforcement directly contravenes this requirement, posing a significant risk to system security.

Virtual patch generated by CITED Relevance SAGE. Validate in isolated environment before production deployment. Compensating control only - does not replace vendor patch.

SAGE Enrichment Record — provenance & audit hash
ModelQwen/Qwen2.5-72B-Instruct-AWQ
ConfidenceHIGH
Enriched At2026-05-24
SHA-512 Audit Hashc4d851c9e4b195b68e001ef71d876c562296d676ccf1157f03f3ca7e12742e4683b4cf5a9e0722704cdddd0e59ff9da982c19b8831e2e0b2880fcc8b4283cb7b
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