How severe is CVE-2023-22921?

CVE-2023-22921 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires high privileges and user interaction. Impact on confidentiality is low, integrity low, and availability high.

Is CVE-2023-22921 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (39th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2023-22921?

CVE-2023-22921 affects Zyxel Nbg-418n Firmware. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2023-22921?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2023-22921 published?

CVE-2023-22921 was published on 2023-05-01 and last updated on 2026-06-17.

CVE-2023-22921

CVE-2023-22921 is a high-severity vulnerability in Zyxel Nbg-418n Firmware with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-79.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 1% (39th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Zyxel Nbg-418n Firmware
Published: 2023-05-01
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2023-22921?: 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.
How severe is CVE-2023-22921?: CVE-2023-22921 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires high privileges and user interaction. Impact on confidentiality is low, integrity low, and availability high.
Is CVE-2023-22921 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (39th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2023-22921?: CVE-2023-22921 affects Zyxel Nbg-418n Firmware. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2023-22921?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2023-22921 published?: CVE-2023-22921 was published on 2023-05-01 and last updated on 2026-06-17.

References

https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-multiple-vulnerabilities-in-nbg-418n-v2-home-router

Affected products (1)

cpe:2.3:o:zyxel:nbg-418n_firmware:*:*:*:*:*:*:*:*

More vulnerabilities in Zyxel Nbg-418n Firmware

CVE-2019-6710 — High (CVSS 8.8): Zyxel NBG-418N v2 v1.00(AAXM.4)C0 devices allow login.cgi CSRF.
CVE-2015-7283 — High (CVSS 8.1): The web administration interface on ZyXEL NBG-418N devices with firmware 1.00(AADZ.3)C0 has a default password of 1234…
CVE-2015-7284 — High (CVSS 8.0): Cross-site request forgery (CSRF) vulnerability on ZyXEL NBG-418N devices with firmware 1.00(AADZ.3)C0 allows remote…
CVE-2023-22922 — High (CVSS 7.5): A buffer overflow vulnerability in the Zyxel NBG-418N v2 firmware versions prior to V1.00(AARP.14)C0 could allow a…
CVE-2023-22923 — Medium (CVSS 6.5): A format string vulnerability in a binary of the Zyxel NBG-418N v2 firmware versions prior to V1.00(AARP.14)C0 could…
CVE-2022-45441 — Medium (CVSS 6.1): A cross-site scripting (XSS) vulnerability in Zyxel NBG-418N v2 firmware versions prior to V1.00(AARP.13)C0, which…

All CVEs affecting Zyxel Nbg-418n Firmware →

Other CWE-79 (Cross-site Scripting (XSS)) vulnerabilities

CVE-2025-49410 — Critical (CVSS 10.0): Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in Imran Emu TC…
CVE-2024-47875 — Critical (CVSS 10.0): DOMPurify is a DOM-only, super-fast, uber-tolerant XSS sanitizer for HTML, MathML and SVG. DOMpurify was vulnerable to…
CVE-2024-6886 — Critical (CVSS 10.0): Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting') vulnerability in Gitea…
CVE-2023-45144 — Critical (CVSS 10.0): com.xwiki.identity-oauth:identity-oauth-ui is a package to aid in building identity and service providers based on…
CVE-2023-45138 — Critical (CVSS 10.0): Change Request is an pplication allowing users to request changes on a wiki without publishing the changes directly.…
CVE-2022-4361 — Critical (CVSS 10.0): Keycloak, an open-source identity and access management solution, has a cross-site scripting (XSS) vulnerability in the…

Browse all CWE-79 (Cross-site Scripting (XSS)) vulnerabilities →