CVE-2023-22921 — A cross-site scripting (XSS) vulnerability in the Zyxel NBG-418N v2 firmware ver

A cross-site scripting (XSS) vulnerability in the Zyxel NBG-418N v2 firmware versions prior to V1.00(AARP.14)C0 could allow a remote authenticated attacker with administrator privileges to store malicious scripts using a web management interface parameter, resulting in denial-of-

01What is this vulnerability?

A cross-site scripting (XSS) vulnerability in the Zyxel NBG-418N v2 firmware versions prior to V1.00(AARP.14)C0 could allow a remote authenticated attacker with administrator privileges to store malicious scripts using a web management interface parameter, resulting in denial-of-service (DoS) conditions on an affected device.

02Affected products

Vendor	Product	Versions
Zyxel	NBG	418N v2 firmware — < V1.00(AARP.14)C0

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2023-05-01T00:00:00.000Z
• Last modified: 2025-01-30T16:49:28.838Z

09References

• www.zyxel.com — https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advis…