# CVE-2026-4252: Tenda AC8 IPv6 check_is_ipv6 ip address for authentication

> Attackers can bypass authentication on Tenda AC8 routers by exploiting IPv6 address reliance in the check_is_ipv6 function.

- **Severity:** Critical 9.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 16 Mar 2026
- **Updated:** 16 Mar 2026
- **Also known as:** GHSA-7fp9-cvqr-rwmf

## What is CVE-2026-4252?

CVE-2026-4252 is a critical authentication bypass vulnerability in Tenda Ac8 Firmware, published on 16 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A vulnerability was identified in Tenda AC8 16.03.50.11. Affected by this issue is the function check_is_ipv6 of the component IPv6 Handler. The manipulation leads to reliance on ip address for authentication. It is possible to initiate the attack remotely. The exploit is publicly available and might be used.

Weakness: CWE-291 (Reliance on IP Address for Authentication), CWE-287 (Improper Authentication)

## Which versions are affected by CVE-2026-4252?

It affects 1 product.


Products: Tenda Ac8 Firmware.

## How do I fix CVE-2026-4252?

No fix has been published for CVE-2026-4252 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-4252 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-4252 exists.

## Other vulnerabilities in Tenda Ac8 Firmware

- [CVE-2025-29100](https://insights.sbomify.com/CVE-2025-29100/): Memory corruption in n/a (critical 9.8)
- [CVE-2025-25663](https://insights.sbomify.com/CVE-2025-25663/): Memory corruption in n/a (critical 9.8)
- [CVE-2025-25664](https://insights.sbomify.com/CVE-2025-25664/): Memory corruption in n/a (critical 9.8)
- [CVE-2025-25667](https://insights.sbomify.com/CVE-2025-25667/): Memory corruption in n/a (critical 9.8)
- [CVE-2025-25668](https://insights.sbomify.com/CVE-2025-25668/): Memory corruption in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-4252 and fix it if it is affected.

What it is: CVE-2026-4252 is a critical authentication bypass vulnerability in Tenda Ac8 Firmware, published on 16 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-4252 exists.

Affected product: Tenda Ac8 Firmware. 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-2026-4252/ (Markdown: https://insights.sbomify.com/CVE-2026-4252/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-4252
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-4252
- OSV: https://osv.dev/vulnerability/CVE-2026-4252

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-4252/
Summaries are generated and may contain mistakes; the official description above is the record.