# CVE-2026-76873: Netcore NR255-V stored cross-site scripting in DHCP and ARP hostname fields

Source: https://junglewise.ai/threats/cve-2026-76873-netcore-nr255-v-stored-cross-site-scripting-in-dhcp-and-arp  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-15. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-76873 · Severity: medium · CVSS 5.2 · Published 2026-09-15

The Netcore NR255-V is a residential network router used to connect devices to the internet. This vulnerability allows an attacker on the local network to inject malicious scripts through DHCP hostname fields, which are later displayed in the router's web management interface. If a network administrator views the affected pages, their browser could execute the attacker's script, potentially allowing unauthorized access to router settings or theft of administrative credentials.

Technologies: [Netcore NR255-V](https://junglewise.ai/threats/technologies/nr255-v). Vendors: [Netcore](https://junglewise.ai/threats/vendors/netcore).

## Quick answers

**Is CVE-2026-76873 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-76873 being exploited in the wild.

**How severe is CVE-2026-76873?** Medium severity, with a CVSS score of 5.2, published 15 September 2026.

**Which products and versions are affected?** Netcore NR255-V 1.5.130703.

**Is there a fix for CVE-2026-76873?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-76873 attacked?** It is attacked from the adjacent network, in a network appliance.

**Am I affected by CVE-2026-76873?** Check whether you run Netcore NR255-V at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

This is a stored cross-site scripting (XSS) vulnerability in the DHCP dynamic IP display and ARP bind list display components of the web management interface. The vulnerability exists in the hostname field handling code (dhcp_dynamicip_show_cgi.c and arp_bind_list_show_cgi.c), which fails to properly sanitize user-controlled input before rendering it via network_config.js and network_security.js. An attacker with access to the local network (adjacent network vector) can inject arbitrary HTML and JavaScript through hostname fields in DHCP or ARP traffic. When a network administrator accesses the web interface to view these pages, the injected script executes in their browser context. No patch availability is currently documented in the advisory materials.

## Affected products

- Netcore NR255-V 1.5.130703

## Timeline

- 2026-09-04: disclosed
- 2026-09-15: advisory

## References

- [https://github.com/draw-ctf/netcore-router-public-refs/blob/main/2026.08.19-netcore-nr255v-dhcp-lan-xss.md](https://github.com/draw-ctf/netcore-router-public-refs/blob/main/2026.08.19-netcore-nr255v-dhcp-lan-xss.md)
- [https://www.vulncheck.com/advisories/netcore-nr255-v-1.5.130703-stored-cross-site-scripting-via-dhcp-and-arp-hostname-fields](https://www.vulncheck.com/advisories/netcore-nr255-v-1.5.130703-stored-cross-site-scripting-via-dhcp-and-arp-hostname-fields)

## Related threats

- [Netcore NR255-V stored cross-site scripting in L7 content management](https://junglewise.ai/threats/cve-2026-92257-netcore-nr255-v-stored-cross-site-scripting-in-l7-content)
- [Netcore NR255-V sensitive information disclosure in VPN configuration handlers](https://junglewise.ai/threats/cve-2026-92256-netcore-nr255-v-sensitive-information-disclosure-in-vpn)
- [Netcore NR255-V out-of-bounds read in filter_arp_put_file.cgi](https://junglewise.ai/threats/cve-2026-92255-netcore-nr255-v-out-of-bounds-read-in-filter-arp-put-file-cgi)
- [Netcore NR255-V stored cross-site scripting in DHCP and ACL management](https://junglewise.ai/threats/cve-2026-76872-netcore-nr255-v-stored-cross-site-scripting-in-dhcp-and-acl)
- [Netcore NR255-V credential disclosure in VPN components](https://junglewise.ai/threats/cve-2026-76871-netcore-nr255-v-credential-disclosure-in-vpn-components)