CVE-2026-35226 CODESYS CVE debrief

Who should care

Defenders responsible for industrial control systems and networks, particularly those using CODESYS PROFINET Controller, should assess exposure and prioritize verification and patching

Why it matters

CVE-2026-35226 is a high-severity vulnerability in CODESYS PROFINET Controller that allows unauthenticated attackers to trigger PLC application exceptions, potentially disrupting industrial control systems and networks.

• Verify and apply patches or mitigations to prevent potential disruptions
• Assess exposure in industrial control systems and networks to prioritize remediation
• Monitor PLC application logs for exceptions and controlled stops to detect potential attacks

Technical summary

The CODESYS PROFINET Controller is vulnerable to an out-of-bounds write attack, allowing an unauthenticated attacker to send malformed PROFINET communication data that triggers an exception in the affected PLC application, resulting in a controlled stop. The vulnerability has a CVSS score of 7.1 and is considered high severity. Defenders should prioritize verifying and applying patches or mitigations provided by the vendor, and assess exposure in industrial control systems and networks to prevent potential disruptions.

Defensive priority

Defenders should prioritize verifying and applying patches or mitigations provided by the vendor, and assess exposure in industrial control systems and networks.

Recommended defensive actions

• Verify and apply patches or mitigations provided by the vendor
• Assess exposure in industrial control systems and networks
• Monitor PLC application logs for exceptions and controlled stops
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record and NVD entry provide details on the vulnerability, but additional information on affected versions, exploitation, and remediation is limited. The CODESYS PROFINET Controller is a widely used component in industrial control systems, and defenders should verify the affected scope and apply patches or mitigations provided by the vendor. The official CVE Program record and NVD detail page offer source-provided CVE metadata and vulnerability assessment.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.