No exploitation reported

CVE-2023-22915

No exploitation reported by the sources we read.

Published2023-04-24
WeaknessCWE-120

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

A buffer overflow vulnerability in the “fbwifi_forward.cgi” CGI program of Zyxel USG FLEX series firmware versions 4.50 through 5.35, USG FLEX 50(W) firmware versions 4.30 through 5.35, USG20(W)-VPN firmware versions 4.30 through 5.35, and VPN series firmware versions 4.30 through 5.35, which could allow a remote unauthenticated attacker to cause DoS conditions by sending a crafted HTTP request if the Facebook WiFi function were enabled on an affected device.

Timeline

dates in UTC

2023-04-2417:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2023-22915?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2023-22915?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Zyxel usg 20w-vpn firmwareversion to verify

Branch	Affected	Fixed in	Source
5.35	≥ 4.30, ≤ 5.35	no fix published	NVD

Zyxel usg flex 100 firmwareversion to verify

Branch	Affected	Fixed in	Source
5.35	≥ 4.50, ≤ 5.35	no fix published	NVD

Zyxel usg flex 100w firmwareversion to verify

Branch	Affected	Fixed in	Source
5.35	≥ 4.50, ≤ 5.35	no fix published	NVD

9 more products in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Advisories and patches

www.zyxel.comVendor Advisory

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

CISA-ADPSSVC decisionnone2025-02-04
OpenCVESSVC decisionnone—
CNACVSS 3.17.5read 2026-10-23
NVDCVSS 3.17.5read 2026-10-23
CNAweakness (CWE)CWE-120read 2026-10-23
NVDweakness (CWE)CWE-120read 2026-10-23
FIRST EPSSEPSS score1.1 %2026-10-22

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published: 2023-04-24
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2023-22915?

Is CVE-2023-22915 actively exploited?

Active exploitation of CVE-2023-22915 has not been confirmed. Its EPSS score was 1.1% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2023-22915?

CVE-2023-22915 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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