# CVE-2026-76869: Netcore NR255-V stack-based buffer overflow in reboot_timer_set.cgi

Source: https://junglewise.ai/threats/cve-2026-76869-netcore-nr255-v-stack-based-buffer-overflow-in-reboot-timer-set  
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-2026-76869 · Severity: high · CVSS 7.2 · Published 2026-09-15

Netcore NR255-V is a wireless router used in home and small-office networks. A stack-based buffer overflow flaw in the reboot timer management interface allows authenticated attackers to corrupt router memory by submitting malformed input, potentially leading to code execution and complete device compromise.

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

## Quick answers

**Is CVE-2026-76869 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-76869 being exploited in the wild.

**How severe is CVE-2026-76869?** High severity, with a CVSS score of 7.2, published 15 September 2026.

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

**Is there a fix for CVE-2026-76869?** 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-2026-76869 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-76869?** 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

A stack-based buffer overflow (CWE-121) exists in the reboot_timer_set.cgi endpoint, caused by improper sscanf token parsing that fails to validate input length before writing to a fixed-size stack buffer. The vulnerability is network-accessible but requires authentication (administrator privileges) to trigger. An attacker with valid credentials can send crafted POST/GET requests to the vulnerable endpoint to overwrite the stack, potentially achieving arbitrary code execution on the router. A patch or firmware update from Netcore has not been announced as of the advisory publication date.

## Affected products

- Netcore NR255-V 1.5.130703

## Timeline

- 2026-09-15: disclosed: CVE-2026-76869 published
- 2026-08-19: other: Public research disclosure on GitHub

## References

- [https://github.com/draw-ctf/netcore-router-public-refs/blob/main/2026.08.19-netcore-nr255v-reboot-timer-overflow.md](https://github.com/draw-ctf/netcore-router-public-refs/blob/main/2026.08.19-netcore-nr255v-reboot-timer-overflow.md)
- [https://www.vulncheck.com/advisories/netcore-nr255-v-1.5.130703-stack-based-buffer-overflow-in-reboot-timer-set-cgi](https://www.vulncheck.com/advisories/netcore-nr255-v-1.5.130703-stack-based-buffer-overflow-in-reboot-timer-set-cgi)

## 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 ARP hostname fields](https://junglewise.ai/threats/cve-2026-76873-netcore-nr255-v-stored-cross-site-scripting-in-dhcp-and-arp)
- [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)