VulnTideExploited vulnerabilities, by vendor. Data as of .
Not in CISA KEVReported exploited: VulnCheck KEV since Published CVSS 9.8 criticalEPSS 5.4% probability of exploitation in 30 days
Zyxel

CVE-2023-28769: The buffer overflow vulnerability in the library “libclinkc.so” of the web server “zhttpd” in Zyxel DX5401-B0 firmwar…

Is it exploited?

Reported, not confirmed by CISA. VulnCheck KEV lists it as exploited in the wild. CISA has not added it to its Known Exploited Vulnerabilities catalog as of .

VulnCheck KEV lists it since . It cites 1 public report, the first from .

How likely is exploitation in the next 30 days?
5.4%

EPSS score, percentile 92.7 of all scored records. A probability estimated by FIRST, not a report of exploitation.

How severe?
9.8 Critical

CVSS v3.1 base score, given by the CNA

What should I do?

CISA has set no required action, because the vulnerability is not in KEV.

The CVE record links no vendor advisory, patch or mitigation.

Which versions are affected?

Affected

  • < V5.17(ABYO.1)C0

Versions by product

Source: CISA KEV 2026.10.29, as of ; VulnCheck KEV, as of ; FIRST EPSS, as of ; CVE List, as of . About the data.

Description

The buffer overflow vulnerability in the library “libclinkc.so” of the web server “zhttpd” in Zyxel DX5401-B0 firmware versions prior to V5.17(ABYO.1)C0 could allow a remote unauthenticated attacker to execute some OS commands or to cause denial-of-service (DoS) conditions on a vulnerable device.

Source: CVE List, as of . About the data.

What to do

Advisories and patches

The CVE record links no vendor advisory, patch or mitigation.

This summary is based on the CVE record as of . Check the vendor's advisory before you act: affected versions and fixes can change.

Affected products and versions

Versions by product, as listed in the CVE record (1 product)
Zyxel DX5401-B0 firmware
StatusVersions
Affected< V5.17(ABYO.1)C0

Source: CVE List, as of . About the data.

Weakness

CWE-120
  • CWE-120: Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')

CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record.

Timeline

DateEvent
CVE record published
CVE record last updated

References

1

Known exploited Zyxel vulnerabilities

  • CVE-2026-7273: Zyxel GS1900 Series Switches Stack-Based Buffer Overflow Vulnerability (added )
  • CVE-2024-40890: Zyxel DSL CPE OS Command Injection Vulnerability (added )
  • CVE-2024-40891: Zyxel DSL CPE OS Command Injection Vulnerability (added )
  • CVE-2024-11667: Zyxel Multiple Firewalls Path Traversal Vulnerability (added )
  • CVE-2017-6884: Zyxel EMG2926 Routers Command Injection Vulnerability (added )