CVE-2025-40570VulnerabilityPublished 12 Aug 2025

CVE-2025-40570: Siemens SIPROTEC 5 6MD84 (CP300) · Unthrottled Resource Allocation

Affects Siemens SIPROTEC 5 6MD84 (CP300)Source CVE Database V5

Not known to be exploited · CVSS 2.4 Low.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 3.1 base score

2.4Low

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

EPSS: 0.1% chance of exploitation in 30 days – higher than 9% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

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

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

Attack Vector: Physical: The attack requires the attacker to physically touch or manipulate the vulnerable component. Physical interaction may be brief or persistent.
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: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the impacted component are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 12 Aug 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 2026-10-26.

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
Siemens SIPROTEC 5 6MD84 (CP300)	Affected =0	Fixed in–

AI-suggested

1. Restrict physical access to SIPROTEC 5 devices, especially their USB ports, through enhanced physical security controls such as locked cabinets, surveillance, and access logging. 2. Implement strict personnel vetting and monitoring to reduce insider threat risks. 3. Disable or restrict USB network interfaces if not required for operational purposes to eliminate the attack surface. 4. Monitor device logs and network traffic for unusual high-bandwidth activity on USB interfaces that could indicate exploitation attempts. 5. Coordinate with Siemens for timely firmware updates or patches once available and plan for scheduled device maintenance to apply fixes. 6. Employ network segmentation and isolation strategies to limit exposure of critical devices to unauthorized access. 7. Develop incident response procedures specifically addressing DoS conditions on SIPROTEC devices to ensure rapid recovery and continuity. 8. Consider deploying additional redundant protection relays or failover mechanisms to maintain grid stability in case of device resets or outages.

Description

A vulnerability has been identified in SIPROTEC 5 6MD84 (CP300) (All versions < V10.0), SIPROTEC 5 6MD85 (CP300) (All versions >= V7.80 < V10.0), SIPROTEC 5 6MD86 (CP300) (All versions >= V7.80 < V10.0), SIPROTEC 5 6MD89 (CP300) (All versions >= V7.80 < V10.0), SIPROTEC 5 6MU85 (CP300) (All versions >= V7.80 < V10.0), SIPROTEC 5 7KE85 (CP300) (All versions >= V7.80 < V10.0), SIPROTEC 5 7SA82 (CP150) (All versions < V10.0), SIPROTEC 5 7SA86 (CP300) (All versions >= V7.80 < V10.0), SIPROTEC 5 7SA87 (CP300) (All versions >= V7.80 < V10.0), SIPROTEC 5 7SD82 (CP150) (All versions < V10.0), SIPROTEC 5 7SD86 (CP300) (All versions >= V7.80 < V10.0), SIPROTEC 5 7SD87 (CP300) (All versions >= V7.80 < V10.0), SIPROTEC 5 7SJ81 (CP150) (All versions < V10.0), SIPROTEC 5 7SJ82 (CP150) (All versions < V10.0), SIPROTEC 5 7SJ85 (CP300) (All versions >= V7.80 < V10.0), SIPROTEC 5 7SJ86 (CP300) (All versions >= V7.80 < V10.0), SIPROTEC 5 7SK82 (CP150) (All versions < V10.0), SIPROTEC 5 7SK85 (CP300) (All versions >= V7.80 < V10.0), SIPROTEC 5 7SL82 (CP150) (All versions < V10.0), SIPROTEC 5 7SL86 (CP300) (All versions >= V7.80 < V10.0), SIPROTEC 5 7SL87 (CP300) (All versions >= V7.80 < V10.0), SIPROTEC 5 7SS85 (CP300) (All versions >= V7.80 < V10.0), SIPROTEC 5 7ST85 (CP300) (All versions < V10.0), SIPROTEC 5 7ST86 (CP300) (All versions < V10.0), SIPROTEC 5 7SX82 (CP150) (All versions < V10.0), SIPROTEC 5 7SX85 (CP300) (All versions < V10.0), SIPROTEC 5 7SY82 (CP150) (All versions < V10.0), SIPROTEC 5 7UM85 (CP300) (All versions >= V7.80 < V10.0), SIPROTEC 5 7UT82 (CP150) (All versions < V10.0), SIPROTEC 5 7UT85 (CP300) (All versions >= V7.80 < V10.0), SIPROTEC 5 7UT86 (CP300) (All versions >= V7.80 < V10.0), SIPROTEC 5 7UT87 (CP300) (All versions >= V7.80 < V10.0), SIPROTEC 5 7VE85 (CP300) (All versions >= V7.80 < V10.0), SIPROTEC 5 7VK87 (CP300) (All versions >= V7.80 < V10.0), SIPROTEC 5 7VU85 (CP300) (All versions < V10.0), SIPROTEC 5 Compact 7SX800 (CP050) (All versions < V10.0). Affected devices do not properly limit the bandwidth for incoming network packets over their local USB port. This could allow an attacker with physical access to send specially crafted packets with high bandwidth to the affected devices thus forcing them to exhaust their memory and stop responding to any network traffic via the local USB port. Affected devices reset themselves automatically after a successful attack. The protection function is not affected of this vulnerability.

Impact

For European organizations, especially those operating critical infrastructure such as electrical utilities and grid operators, this vulnerability poses a risk of localized denial of service on SIPROTEC 5 devices. Although the core protection functions remain intact, disruption of network communication via the USB port can hinder device management, monitoring, and diagnostics, potentially delaying response times during incidents. The requirement for physical access limits the attack vector primarily to insider threats or attackers with physical proximity to the devices, such as maintenance personnel or intruders. Given the widespread deployment of Siemens SIPROTEC 5 devices across European power grids, any disruption could affect operational efficiency and situational awareness. However, the low severity and automatic device reset mitigate the risk of prolonged outages. Still, in high-security environments or where USB network interfaces are critical for operational workflows, this vulnerability could be exploited to cause nuisance DoS or complicate incident response. The lack of impact on confidentiality and integrity reduces the risk of data compromise or control manipulation, but availability impacts remain a concern in safety-critical systems.

Summary

CVE-2025-40570 is a resource exhaustion vulnerability affecting multiple Siemens SIPROTEC 5 relay devices, specifically models with CP150 and CP300 communication processors, across various versions prior to V10.0. The vulnerability arises because these devices do not properly limit the bandwidth of incoming network packets over their local USB port. An attacker with physical access to the device can exploit this by sending specially crafted high-bandwidth packets through the USB interface. This causes the device to consume excessive memory resources, leading to exhaustion and a denial of service (DoS) condition where the device stops responding to any network traffic via the local USB port. After the attack, the device automatically resets itself, but the disruption can impact operational continuity. Importantly, the protection functions of the devices remain unaffected, meaning the core protective relay functions continue to operate despite the DoS on the USB network interface. The vulnerability is classified under CWE-770, which pertains to allocation of resources without limits or throttling, and has a CVSS v3.1 base score of 2.4 (low severity) due to its requirement for physical access, lack of impact on confidentiality or integrity, and limited scope affecting only the USB network interface. No known exploits are currently reported in the wild, and Siemens has not yet published patches for this issue as of the provided data. The vulnerability affects a broad range of SIPROTEC 5 models widely used in electrical grid protection and automation systems.

CWE-770Allocation of Resources Without Limits or Throttling (opens in a new tab)
Base weaknessLikelihood of exploit: HighCWE Top 25 (2025): #25
The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.
Requirements
Clearly specify the minimum and maximum expectations for capabilities, and dictate which behaviors are acceptable when resource allocation reaches limits.
Architecture and Design
Limit the amount of resources that are accessible to unprivileged users. Set per-user limits for resources. Allow the system administrator to define these limits. Be careful to avoid CWE-410.
Architecture and Design
Design throttling mechanisms into the system architecture. The best protection is to limit the amount of resources that an unauthorized user can cause to be expended.
OWASP Cheat Sheets
Abuse Case (opens in a new tab)
OWASP ASVS 4.0.3
V8.1.4 (opens in a new tab)
V13.4.1 (opens in a new tab)
V11.1.4 (opens in a new tab)
Attack patterns
XML Ping of the Death (opens in a new tab)
Exponential Data Expansion (opens in a new tab)
Serialized Data Parameter Blowup (opens in a new tab)
Serialized Data with Nested Payloads (opens in a new tab)
Oversized Serialized Data Payloads (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

cert-portal.siemens.com/productcert/html/ssa-894058.html (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 12 Aug 2025, 11:51 UTC

WeaknessesCWE-770

Technical details

References

Community reviews

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