Security readout for executives and security teams
Plain-English summary
This vulnerability can let a crafted Modbus packet crash certain Schneider Electric Modicon controllers, causing a denial of service until the device restarts. For industrial environments, the business concern is process disruption, not data theft. The source bundle does not provide a CVSS score or evidence of active exploitation.
Executive priority
Treat this as an operational resilience issue for environments using affected Modicon controllers. Prioritize plants or sites where controller downtime affects safety, production, or service commitments, especially if Modbus access is broadly reachable.
Technical view
CVE-2018-7851 is a CWE-119 buffer error affecting Modicon M580, M340, BMxCRA312xx, Modicon Premium, and 140CRA312xxx firmware versions listed in the CVE. A specially crafted Modbus packet can trigger device denial of service and require restart to restore availability.
Likely exposure
Exposure is most relevant where affected Modicon devices can receive Modbus traffic from engineering networks, plant networks, remote access paths, or compromised internal hosts. Internet exposure is not stated in the sources and should not be assumed.
Exploitation context
The provided sources describe a crafted Modbus packet causing denial of service. They do not cite public exploitation, KEV listing, exploit availability, or attacker prerequisites beyond packet delivery to the affected device.
Researcher notes
The source bundle lacks CVSS, detailed vendor mitigations, and exploit-status evidence. Analysis should stay scoped to denial of service via crafted Modbus traffic against the listed Schneider Electric Modicon products and firmware ranges.
Mitigation direction
- Review Schneider Electric advisory SEVD-2019-134-10 for official remediation guidance.
- Update M580, M340, and BMxCRA312xx firmware beyond affected versions where supported.
- For Modicon Premium and 140CRA312xxx, follow vendor guidance because all firmware versions are listed affected.
- Restrict Modbus access to trusted management and control systems only.
- Monitor affected controllers for unexpected restarts or availability loss.
Validation and detection
- Inventory Modicon M580, M340, BMxCRA312xx, Premium, and 140CRA312xxx assets.
- Record firmware versions and compare them with the affected version thresholds.
- Identify networks and remote access paths that can send Modbus traffic to these devices.
- Check incident logs for unexplained controller restarts or denial-of-service symptoms.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-119: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2018-7851 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS and timeline data
No CVSS vectors or timeline events were available in the normalized CVE source material.
Source materials
- CVE List V5 sourceCVE List V5
- https://www.schneider-electric.com/en/download/document/SEVD-2019-134-10/CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.