CVE-2011-4861

CRITICAL

The modbus_125_handler function in the Schneider Electric Quantum Ethernet Module on the NOE 771 device (aka the Quantum 140NOE771* module) allows remote attackers to install arbitrary firmware upd...

Affects 3 products across 1 vendor.

BCS8.11
CVSS 2.010.0
EPSS3.0%
Percentile86th
PatchUnknown
CVSS Vector — Plain English Remotely exploitable over the network, low complexity.
CWE Weakness Definitions
CWE-264: Permissions, Privileges, and Access Controls

Broad class covering failures in permission enforcement. Deprecated in favor of CWE-284, CWE-862, CWE-863.

◆ SAGE Intelligence — CITED Relevance Research Team

The Schneider Electric Quantum Ethernet Module (NOE 771) contains a vulnerability in the modbus_125_handler function that allows remote attackers to install arbitrary firmware updates via a MODBUS 125 function code to TCP port 502. This vulnerability has a CVSS score of 10.0, indicating critical severity, but the exploitation likelihood is low due to the lack of public proof-of-concept and exploits.

BSID: BS-2011-GLOBAL-316555-C • Model: Qwen/Qwen2.5-72B-Instruct-AWQ • Confidence: MEDIUM

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Frequently Asked Questions
What is CVE-2011-4861?
The Schneider Electric Quantum Ethernet Module (NOE 771) contains a vulnerability in the modbus_125_handler function that allows remote attackers to install arbitrary firmware updates via a MODBUS 125 function code to TCP port 502. This vulnerability has a CVSS score of 10.0, indicating critical severity, but the exploitation likelihood is low due to the lack of public proof-of-concept and exploits.
What is the CVSS score for CVE-2011-4861?
CVE-2011-4861 has CVSS 10.0 (Critical). Vector: AV:N/AC:L/Au:N/C:C/I:C/A:C. EPSS: 3.0%.
Is CVE-2011-4861 actively exploited?
No confirmed active exploitation of CVE-2011-4861 as of 2026-05-30.
How do I remediate CVE-2011-4861?
Priority: MEDIUM.
What systems are affected by CVE-2011-4861?
CVE-2011-4861 affects: Schneider-Electric, Schneider-Electric, Schneider-Electric.
What NERC-CIP standard applies to CVE-2011-4861?
NERC CIP CIP-007 CIP-007-R2: This CVE violates CIP-007-R2 because it allows unauthorized access to the control system, which could compromise the security of the electronic security perimeter.
What IEC 62443 requirement maps to CVE-2011-4861?
IEC 62443 SR 7.6: This CVE maps to SR 7.6 because it involves a vulnerability that could allow an attacker to perform unauthorized changes to the firmware of the device, which is a critical security concern in ICS environments.
Vulnerability Details
CVE IDCVE-2011-4861
BSIDBS-2011-GLOBAL-316555-C BreachSpider Global ID
CVSS VectorAV:N/AC:L/Au:N/C:C/I:C/A:C
Published2011-12-17
Last Modified2026-04-29
ICS Relevance55%
Weakness (CWE)
Verticals
ICS-OT
SourceNVD
Official Description

The modbus_125_handler function in the Schneider Electric Quantum Ethernet Module on the NOE 771 device (aka the Quantum 140NOE771* module) allows remote attackers to install arbitrary firmware updates via a MODBUS 125 function code to TCP port 502.

Source: NIST NVD / MITRE CVE Database

Attack Vector Analysis — CITED Relevance

Remote attackers can exploit the modbus_125_handler function by sending a MODBUS 125 function code to TCP port 502, which allows them to install arbitrary firmware updates on the affected device. This can lead to complete control over the device, including potential denial of service, data corruption, and unauthorized access to the control system.

Exploitation Likelihood: LOW

Affected Products
VendorProductFixed Version
Schneider-Electric Quantum Ethernet Module 140Noe77100
Schneider-Electric Quantum Ethernet Module 140Noe77101
Schneider-Electric Quantum Ethernet Module 140Noe77111
Remediation

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

Threat Intelligence
● Threat Intelligence Validated: August 2026 | Threat Age: 5345 Days
CISA KEVNot in KEV catalog
Public ExploitNot confirmed
PoC CodeNot confirmed
● Virtual Patch — CITED Relevance SAGE Engine MEDIUM CONFIDENCE

Implement network segmentation and access controls to restrict communication to the affected device only from trusted sources. Monitor traffic to TCP port 502 for suspicious activity.

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 because it allows unauthorized access to the control system, which could compromise the security of the electronic security perimeter.
IEC 62443: SR 7.6
This CVE maps to SR 7.6 because it involves a vulnerability that could allow an attacker to perform unauthorized changes to the firmware of the device, which is a critical security concern in ICS environments.

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
ConfidenceMEDIUM
Enriched At2026-05-24
SHA-512 Audit Hashc64e68e2272112175378fd799297116bc411736837650ce193a0591be018cded205c62bca7736a53e11cbe8c1e63032686243dca84aff5e1c3a5ff631a0e7ece
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