CVE-2025-7673Network attack vector

Unauthenticated code execution via crafted HTTP request

Published Jul 16, 2025 · Updated Feb 26, 2026

A buffer overflow in the zhttpd URL parser in Zyxel VMG8825-T50K firmware before V5.50(ABOM.5)C0 allows remote attackers to execute code. Zyxel has not disclosed which parser operation writes beyond the destination buffer when processing the untrusted URL. A crafted HTTP request reaches the flaw without authentication and can crash the gateway or execute arbitrary code.

CVSS severity9.8
Critical
EPSS probability0.55%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A buffer overflow in the zhttpd URL parser in Zyxel VMG8825-T50K firmware before V5.50(ABOM.5)C0 allows remote attackers to execute code. Zyxel has not disclosed which parser operation writes beyond the destination buffer when processing the untrusted URL. A crafted HTTP request reaches the flaw without authentication and can crash the gateway or execute arbitrary code.

The record

CVE
CVE-2025-7673
Published
Jul 16, 2025
Updated
Feb 26, 2026
Vendor
Zyxel Networks
Product
VMG8825-T50K Firmware
Classifications
CWE-120, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 16, 2025CVE publishedPublication date reported by the CVE source.
  2. Feb 26, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< V5.50(ABOM.5)C0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Zyxel Networks · VMG8825-T50K Firmwareversion=< V5.50(ABOM.5)C0

Published CVSS scores

9.8ZyxelCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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