# CVE-2026-76852: Netcore NR268 1.7.121109 Forgeable Firmware Authenticity Check in mtd_write

> Attackers can bypass firmware signature validation on Netcore NR268 routers to load unauthorized firmware, enabling code execution and privilege escalation.

- **Severity:** High 8.7 (`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`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 15 Sep 2026
- **Updated:** 17 Sep 2026
- **Also known as:** GHSA-6645-rfg8-rhrm

## What is CVE-2026-76852?

CVE-2026-76852 is a high-severity vulnerability in Netcore NR268, published on 15 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Netcore NR268 firmware version 1.7.121109 has an improper integrity verification flaw in mtd_write allowing forged firmware authenticity checks. Attackers can exploit put_file.cgi and check_image_uuid.c to bypass firmware signature validation and load unauthorized firmware images.

Weakness: CWE-354 (Improper Validation of Integrity Check Value)

## Which versions are affected by CVE-2026-76852?


## How do I fix CVE-2026-76852?

No fix has been published for CVE-2026-76852 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-76852 being exploited?

There is no known exploitation of CVE-2026-76852 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-76852 and fix it if it is affected.

What it is: CVE-2026-76852 is a high-severity vulnerability in Netcore NR268, published on 15 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-76852 in the wild and no public exploit code.

Affected product: Netcore NR268. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-76852/ (Markdown: https://insights.sbomify.com/CVE-2026-76852/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-76852
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-76852
- OSV: https://osv.dev/vulnerability/CVE-2026-76852

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-76852/
Summaries are generated and may contain mistakes; the official description above is the record.