A buffer overflow vulnerability in the CGI program of Zyxel ATP series firmware versions from V4.32 through V5.38, USG FLEX series firmware…

published 2024-09-03 2 y ago modified 2026-06-17 4 mo ago also EUVD-2024-47456

cvss: 4.9; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.6%; EPSS 0.6% chance of exploitation in 30 days, percentile 49%
public exploits: 0; none known

A buffer overflow vulnerability in the CGI program of Zyxel ATP series firmware versions from V4.32 through V5.38, USG FLEX series firmware versions from V4.50 through V5.38, USG FLEX 50(W) series firmware versions from V4.16 through V5.38, and USG20(W)-VPN series firmware versions from V4.16 through V5.38 could allow an authenticated attacker with administrator privileges to cause denial of service (DoS) conditions by sending a crafted HTTP request to a vulnerable device.

Patch / fix

fixed in 1

zyxel zld 5.39

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 2 y ago (2024-09-03)

Exploit prediction

0.60% chance of exploitation in the next 30 days, higher than 49% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	4.9	CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H

Affected products

Zyxel ATP series firmware
Zyxel USG FLEX series firmware
Zyxel USG FLEX 50(W) series firmware
Zyxel USG20(W)-VPN series firmware

Classification

Weakness

CWE-120 Buffer Copy without Checking Size of Input

References

zyxel.com /global/en/support/security-advisories/zyxel-security-advisory-for-multiple-vulnerabilities-in-firewalls-09-03
vendor-advisory

Sources

CVE List CVE-2024-6343
NVD CVE-2024-6343

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary