Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HSummary
CVE-2025-7673 is a critical-severity Classic Buffer Overflow (CWE-120) vulnerability in Zyxel Emg3525-T50B Firmware. Its CVSS base score is 9.8 (Critical).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 43th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
A buffer overflow vulnerability exists in the URL parser of the zhttpd web server component within Zyxel VMG8825-T50K firmware versions prior to V5.50(ABOM.5)C0. The flaw is tracked as CVE-2025-7673 and assigned CWE-120, with a CVSS 3.1 base score of 9.8 reflecting network attack vector, low complexity, no required privileges or user interaction, and full impact on confidentiality, integrity, and availability.
An unauthenticated remote attacker can exploit the issue by sending a specially crafted HTTP request to the affected device, resulting in denial-of-service conditions or potential arbitrary code execution.
The referenced Zyxel security advisory addresses remote code execution and denial-of-service vulnerabilities in the affected CPE and identifies the patched firmware version V5.50(ABOM.5)C0 as the corrective release. The EPSS score remains low, with a current value of 0.0141 and a peak of 0.0172.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2025-21579
Vulnerability Data
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…
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crafted HTTP request.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V5.2.1
Mitigating Controls (NIST 800-53 r5) AI
Developer testing and analysis can find missing size checks before deployment.
Input validation directly enforces size checks before buffer copies.
Engineering principles require bounds checking and safe buffer handling in design.
Memory protection limits the impact of an overflow once it occurs.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure development practices directly enforce bounds checking and input validation that prevent classic buffer overflows.
Vulnerability identification processes such as code review or scanning detect classic buffer overflows before exploitation.
Routine patching replaces vulnerable code containing unchecked buffer copies with corrected versions.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Secure coding directly requires bounds-checked memory operations, addressing the root cause of CWE-120.
Security testing in development and acceptance can detect buffer overflows through fuzzing and static analysis, though it does not prevent them at the source.
Secure development life cycle mandates processes that can include input validation and bounds checking to prevent buffer overflows.
Application security requirements can specify input-size validation and safe buffer handling to mitigate classic buffer overflows.
Secure system architecture and engineering principles promote defensive coding patterns that reduce the likelihood of unchecked buffer copies.