Cyber Resilience

CVE-2023-28769

Memory Safety in Zyxel Dx5401-B0 Firmware ≤ 5.17\(abyo.1\)c0

Memory Safety
Published
27 April 2023
Modified
21 November 2024
Patch / advisory
View advisory
CVSS Score v3.1 9.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.054 92th percentile
Risk Priority 97 floored blend · peak EPSS

Summary

CVE-2023-28769 is a critical-severity Classic Buffer Overflow (CWE-120) vulnerability in Zyxel Dx5401-B0 Firmware. Its CVSS base score is 9.8 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked in the top 8% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

The vulnerability is a buffer overflow (CWE-120) in the libclinkc.so library used by the zhttpd web server component of Zyxel DX5401-B0 firmware versions prior to V5.17(ABYO.1)C0. With a CVSS 3.1 score of 9.8, the flaw resides in network-facing code that processes unauthenticated requests.

A remote attacker with no credentials or user interaction can send crafted input over the network to trigger the overflow, resulting in arbitrary OS command execution or denial-of-service conditions on the affected device.

Zyxel’s security advisory directs customers to upgrade to firmware V5.17(ABYO.1)C0 or later; the associated EPSS score has remained elevated, currently at 0.7219 with a recorded peak of 0.7417.

EU & UK References

Vulnerability Data

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…

more

vulnerable device.

CWE(s)
CWE-120

Related Threats

MITRE ATT&CK Enterprise Techniques

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
attack.mitre.org →
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
attack.mitre.org →
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
attack.mitre.org →
T1212 Exploitation for Credential Access Credential Access
Adversaries may exploit software vulnerabilities in an attempt to collect credentials.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2023-37929Same product: Zyxel Dx5401-B0
CVE-2024-9197Same product: Zyxel Dx5401-B0
CVE-2024-5412Same product: Zyxel Dx5401-B0
CVE-2024-8748Same product: Zyxel Dx5401-B0
CVE-2024-0816Same product: Zyxel Dx5401-B0
CVE-2023-33009Same vendor: Zyxel
CVE-2025-7673Same vendor: Zyxel
CVE-2026-7287Same vendor: Zyxel
CVE-2024-8882Same vendor: Zyxel
CVE-2023-43314Same vendor: Zyxel

Affected Assets

zyxel
dx5401-b0 firmware
≤ 5.17\(abyo.1\)c0

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V5.2.1

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

SC-27 Platform-independent Applications
addresses: CWE-120

Platform-independent managed code eliminates the need for unchecked native buffer copies that are the root cause of classic buffer overflows.

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.

PR.PS-06 mostly match
prevents

Secure development practices directly enforce bounds checking and input validation that prevent classic buffer overflows.

ID.RA-01 partial match
prevents

Vulnerability identification processes such as code review or scanning detect classic buffer overflows before exploitation.

PR.PS-02 partial match
prevents

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.

A.8.28 Secure coding mostly match
prevents

Secure coding directly requires bounds-checked memory operations, addressing the root cause of CWE-120.

A.8.29 Security testing in development and acceptance mostly match
finds

Security testing in development and acceptance can detect buffer overflows through fuzzing and static analysis, though it does not prevent them at the source.

A.8.25 Secure development life cycle partial match
prevents

Secure development life cycle mandates processes that can include input validation and bounds checking to prevent buffer overflows.

A.8.26 Application security requirements partial match
prevents

Application security requirements can specify input-size validation and safe buffer handling to mitigate classic buffer overflows.

A.8.27 Secure system architecture and engineering principles partial match
prevents

Secure system architecture and engineering principles promote defensive coding patterns that reduce the likelihood of unchecked buffer copies.

References