# A vulnerability in specific versions of Zyxel NBG6818, NBG7815, WSQ20, WSQ50, WSQ60, and WSR30 firmware with pre-configured password management could allow an attacker to obtain root access of the de…

CVE record · `CVE-2021-35033`

- **Identifiers:** `CVE-2021-35033`
- **State:** Confirmed
- **Severity:** CVSS 7.8 High
- **Critical:** No
- **CNA:** Zyxel
- **Weakness (CWE):** [CWE-260](https://cwe.mitre.org/data/definitions/260.html)
- **Tags:** [CWE-260](https://agentprime.io/advisories/tag/cwe-260.md)
- **Technologies:** [Zyxel NBG6818 series firmware](https://agentprime.io/advisories/technology/zyxel-nbg6818-series-firmware.md) · [Zyxel NBG7815 series firmware](https://agentprime.io/advisories/technology/zyxel-nbg7815-series-firmware.md) · [Zyxel WSQ20 series firmware](https://agentprime.io/advisories/technology/zyxel-wsq20-series-firmware.md) · [Zyxel WSQ50 series firmware](https://agentprime.io/advisories/technology/zyxel-wsq50-series-firmware.md) · [Zyxel WSQ60 series firmware](https://agentprime.io/advisories/technology/zyxel-wsq60-series-firmware.md) · [Zyxel WSR30 series firmware](https://agentprime.io/advisories/technology/zyxel-wsr30-series-firmware.md)
- **Published:** 23 Nov 2021
- **Updated:** 4 Aug 2024
- **Reviewed by a person:** No

Published by the CVE Program (CNA: Zyxel) at 23 Nov 2021, 21:20 UTC. agentprime has not analysed this yet, so whether it affects any app is not known. This CVE names a vendor and product rather than a package, so the lockfile check doesn’t match it.

## Affected products, as the CNA wrote them

- Vendor: Zyxel. Product: NBG6818 series firmware.
  - affected: `1.00(ABSC.0)C0 through 1.00(ABSC.4)C0`
- Vendor: Zyxel. Product: NBG7815 series firmware.
  - affected: `1.00(ABSK.0)C0 through 1.00(ABSK.6)C0`
- Vendor: Zyxel. Product: WSQ20 series firmware.
  - affected: `1.00(ABOF.0)C0 through 1.00(ABOF.10)C0`
- Vendor: Zyxel. Product: WSQ50 series firmware.
  - affected: `1.00(ABKJ.0)C0 through 2.20(ABKJ.6)C0`
- Vendor: Zyxel. Product: WSQ60 series firmware.
  - affected: `1.00(ABND.0)C0 through 2.20(ABND.7)C0`
- Vendor: Zyxel. Product: WSR30 series firmware.
  - affected: `1.00(ABMY.0)C0 through 1.00(ABMY.11)C0`

## Not analysed yet

We haven’t published our own analysis of this CVE. If a person reviews it, this page will say what’s affected and what has to be true for it to matter.

## Severity and exploitation

- 7.8 High, CVSS 3.1: `CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H`, from CNA (Zyxel)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0041, the 35th percentile, on 7 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

This record came from the full history of the CVE Program, published 23 Nov 2021. New records show when each source confirmed them.

## Sources

- [CVE List: CVE-2021-35033](https://www.cve.org/CVERecord?id=CVE-2021-35033)
- [NVD: CVE-2021-35033](https://nvd.nist.gov/vuln/detail/CVE-2021-35033)

### References from the CNA

- <https://www.zyxel.com/support/Zyxel_security_advisory_for_pre-configured_password_management_vulnerability_of_home_routers_and_WiFi_systems.shtml> (confirm)
- <https://www.tenable.com/security/research/tra-2022-06>

Facts on this page come from the CVE List as the CNA published them, with CVSS from the sources named above, CISA KEV and FIRST EPSS. Vendors, products and versions are shown as the CNA wrote them. We don’t reproduce the CVE’s description.

## Check whether this affects you

This CVE names a vendor and product rather than a package, so the lockfile check doesn’t match it. Compare the affected versions above with what you run.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), `get_advisory` returns this record and `search_advisories` finds related ones. Setup: <https://agentprime.io/mcp.md>
- As JSON: <https://api.agentprime.io/v1/advisories/CVE-2021-35033>
- Everything that needs attention now: <https://agentprime.io/advisories/critical.md>

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The web page: <https://agentprime.io/advisories/CVE-2021-35033/>. Everything for agents: <https://agentprime.io/llms.txt>.