CVE-2026-76856 Netcore CVE debrief

Who should care

Network administrators responsible for managing Netcore NR255-V devices should assess exposure and prioritize verification and potential updates to prevent configuration tampering.

Why it matters

CVE-2026-76856 is a cross-site request forgery vulnerability in Netcore NR255-V firmware version 1.5.130703, allowing attackers to trick authenticated administrators into modifying network configuration settings. Network administrators should prioritize verifying and updating firmware versions to prevent potential configuration tampering.

• Potential unauthorized modification of WAN or LAN network configuration settings
• Possible disruption of network services or connectivity
• Required verification of firmware version and implementation of additional security measures

Technical summary

The vulnerability exists in the wan_config_set_cgi, wan_num_set_cgi, and lan_ip_change_cgi endpoints of Netcore NR255-V firmware version 1.5.130703, allowing attackers to craft forged requests to trick authenticated administrators into modifying WAN or LAN network configuration settings without consent. This vulnerability allows attackers to modify network configuration settings, potentially disrupting network services or connectivity. Network administrators should prioritize verifying and updating firmware versions to prevent potential configuration tampering.

Defensive priority

Network administrators should prioritize verifying and updating firmware versions to prevent potential configuration tampering.

Recommended defensive actions

• Verify firmware version and update if necessary
• Implement additional security measures to prevent configuration tampering
• Monitor network configuration settings for suspicious activity
• 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, including its CVSS score and affected endpoints. The vulnerability exists in the wan_config_set_cgi, wan_num_set_cgi, and lan_ip_change_cgi endpoints of Netcore NR255-V firmware version 1.5.130703. Attackers can craft forged requests to trick authenticated administrators into modifying WAN or LAN network configuration settings without consent. Network administrators should prioritize verifying and updating firmware versions to prevent potential configuration tampering.

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.