Cyber Resilience

CVE-2023-43240

Memory Safety in Dlink Dir-816 A2 Firmware 1.10cnb05

Public PoCMemory Safety
Published
21 September 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 0.12 96th percentile
Risk Priority 94 floored blend · peak EPSS

Summary

CVE-2023-43240 is a critical-severity Out-of-bounds Write (CWE-787) vulnerability in Dlink Dir-816 A2 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 4% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

Deeper analysis AI-assisted summary

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

D-Link DIR-816 A2 firmware version 1.10CNB05 contains a stack-based buffer overflow in the ipportFilter function triggered by the sip_address parameter. The flaw is tracked as CVE-2023-43240, carries a CVSS 3.1 score of 9.8, and is classified under CWE-787 as an out-of-bounds write.

An unauthenticated attacker with network access can supply a crafted sip_address value to the affected device, resulting in arbitrary code execution, memory corruption, or a denial-of-service condition without any user interaction or credentials.

Public references point to a D-Link security bulletin page and a detailed proof-of-concept description hosted on GitHub, but the bulletin itself provides no additional mitigation steps beyond the general recommendation to monitor vendor advisories for firmware updates.

The associated EPSS score currently sits at 0.58 with a recorded peak of 0.61, indicating sustained exploitation interest after disclosure.

EU & UK References

Vulnerability Data

D-Link DIR-816 A2 v1.10CNB05 was discovered to contain a stack overflow via parameter sip_address in ipportFilter.

CWE(s)
CWE-787

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 →
T1211 Exploitation for Stealth Stealth
Adversaries may exploit vulnerabilities to evade detection by hiding activity, suppressing logging, or operating within trusted or unmonitored components.
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-2023-43238Same product: Dlink Dir-816 A2
CVE-2023-43236Same product: Dlink Dir-816 A2
CVE-2023-43239Same product: Dlink Dir-816 A2
CVE-2023-43237Same product: Dlink Dir-816 A2
CVE-2023-44807Same vendor: Dlink
CVE-2023-37791Same vendor: Dlink
CVE-2023-43860Same vendor: Dlink
CVE-2023-27720Same vendor: Dlink
CVE-2023-43862Same vendor: Dlink
CVE-2023-29665Same vendor: Dlink

Affected Assets

dlink
dir-816 a2 firmware
1.10cnb05

Mitigating Controls

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.

SI-16 Memory Protection
addresses: CWE-787

Out-of-bounds writes that corrupt control flow or inject shellcode are rendered non-executable by the same memory protections.

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 (static analysis, bounds checking, code review) are the primary means of preventing out-of-bounds writes.

ID.RA-01 partial match
prevents

Vulnerability scanning and recording can discover out-of-bounds write flaws so they can be remediated.

PR.PS-02 partial match
prevents

Patching or replacing vulnerable software directly eliminates known instances of this coding weakness.

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.8.29 Security testing in development and acceptance mostly match
finds

Security testing in development and acceptance can detect and prevent out-of-bounds write defects.

A.8.25 Secure development life cycle partial match
prevents

Secure development life cycle mandates practices that prevent out-of-bounds writes.

A.8.26 Application security requirements partial match
prevents

Application security requirements can specify bounds-checking and safe memory handling.

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

Secure architecture and engineering principles reduce the likelihood of buffer overflows.

A.8.28 Secure coding partial match
prevents

Secure coding directly addresses out-of-bounds writes through language choice and coding standards.

A.8.32 Change management partial match
prevents

Change management can enforce review gates that catch unsafe memory operations before deployment.

References