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Vulnerabilities

Vulnerability · CVE-2025-7673

Zyxel emg3525-t50b_firmware Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')

Published Jul 16, 2025 · catalog updated Jul 16, 2025 · Zyxel CPE zhttpd Webserver

Patch now

CVE-2025-7673 is in the CISA known-exploited catalog. Confirm Zyxel CPE zhttpd Webserver against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Gaps on this record

  • No version range is stored. A customer cannot check an installed version against this record.
Severity
Unknown—
Known exploitation
CISA KEV and VulnCheck KEV
EPSS
0.65%
Remediation
Remediation guidance
Affected products
vendor Zyxel CPE zhttpd Webserver

A buffer overflow vulnerability in the URL parser of the zhttpd web server in Zyxel VMG8825-T50K firmware versions prior to V5.50(ABOM.5)C0 could allow an unauthenticated attacker to cause denial-of-service (DoS) conditions and potentially execute arbitrary code by sending a specially crafted HTTP request.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • vendor Zyxel CPE zhttpd Webserverversion unspecified

How to fix CVE-2025-7673

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2025-7673 is in the CISA known-exploited catalog. Confirm Zyxel CPE zhttpd Webserver against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Which versions are affected?

Affected version ranges are not on this record. Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.

What should an analyst verify?

No weakness class is stored. EPSS 0.65%. The CISA KEV listing is the exploitation evidence. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Jul 16, 2025 · VulnCheck KEV

    Detected

    A buffer overflow vulnerability in the URL parser of the zhttpd web server in Zyxel VMG8825-T50K firmware versions prior to V5.50(ABOM.5)C0 could allow an unauthenticated attacker to cause denial-of-service (DoS) conditions and potentially execute arbitrary code by sending a specially crafted HTTP request.

  2. Jul 16, 2025 · CISA KEV

    Known exploited

    Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.

Sources

  • CVE.orgVulnerability recordCVE-2025-7673

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2025-7673

    30-day exploitation probability 0.7%

    first.org
  • VulnCheck KEVConfirmed exploitationCVE-2025-7673

    A buffer overflow vulnerability in the URL parser of the zhttpd web server in Zyxel VMG8825-T50K firmware versions prior to V5.50(ABOM.5)C0 could allow an unauthenticated attacker to cause denial-of-service (DoS) conditions and potentially execute arbitrary code by sending a spec

    vulncheck.com

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.