# CVE-2025-31703: Auth bypass in NVR2-4KS3

> Attackers with physical access can bypass serial port authentication to gain restricted shell access and escalate privileges on Dahua NVR/XVR devices.

- **Severity:** Low 2.4 (`CVSS:4.0/AV:P/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 18 Mar 2026
- **Updated:** 18 Mar 2026
- **Also known as:** GHSA-26qr-26wf-xv6x

## What is CVE-2025-31703?

CVE-2025-31703 is a low-severity authentication bypass vulnerability in dahua NVR2-4KS3, published on 18 Mar 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A vulnerability found in Dahua NVR/XVR device. A third-party malicious attacker with physical access to the device may gain access to a restricted shell via the serial port, and bypasses the shell's authentication mechanism to escalate privileges.

Weakness: CWE-305 (Authentication Bypass by Primary Weakness)

## Which versions are affected by CVE-2025-31703?


## How do I fix CVE-2025-31703?

No fix has been published for CVE-2025-31703 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-31703 being exploited?

There is no known exploitation of CVE-2025-31703 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-31703 and fix it if it is affected.

What it is: CVE-2025-31703 is a low-severity authentication bypass vulnerability in dahua NVR2-4KS3, published on 18 Mar 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-31703 in the wild and no public exploit code.

Affected product: dahua NVR2-4KS3. 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-2025-31703/ (Markdown: https://insights.sbomify.com/CVE-2025-31703/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-31703
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-31703
- OSV: https://osv.dev/vulnerability/CVE-2025-31703

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-31703/
Summaries are generated and may contain mistakes; the official description above is the record.