Security Resilience

CVE-2023-39747

Memory Safety in Tp-Link Tl-Wr940N V2 Firmware

Public PoCMemory Safety
Published
21 August 2023
Modified
21 November 2024
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 0.087 95th percentile
Risk Priority 81 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2023-39747 is a critical-severity Classic Buffer Overflow (CWE-120) vulnerability in Tp-Link Tl-Wr940N V2 Firmware. Its CVSS base score is 9.8 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique NTDS (T1003.003); ranked in the top 5% 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.

TP-Link WR841N V8, TL-WR940N V2, and TL-WR941ND V5 routers contain a stack-based buffer overflow vulnerability (CWE-120) triggered by the radiusSecret parameter in the /userRpm/WlanSecurityRpm endpoint. The flaw received a CVSS 3.1 score of 9.8, reflecting network-accessible input handling without authentication or user interaction.

An unauthenticated remote attacker can supply a crafted radiusSecret value to overflow the buffer, resulting in arbitrary code execution with full control over the device confidentiality, integrity, and availability. The attack requires only a single HTTP request to the management interface and succeeds against the listed firmware versions.

Public references consist of technical write-ups hosted on GitHub that document the parameter handling and reproduction steps; no vendor advisory, firmware patch, or mitigation guidance is referenced in the available sources. The associated EPSS score has remained flat at 0.1254 with no material increase since disclosure.

EU & UK References

Vulnerability Data

TP-Link WR841N V8, TP-Link TL-WR940N V2, and TL-WR941ND V5 were discovered to contain a buffer overflow via the radiusSecret parameter at /userRpm/WlanSecurityRpm.

CWE(s)
CWE-120

Related Threats

MITRE ATT&CK Enterprise Techniques

T1003.003 NTDS Credential Access
Adversaries may attempt to access or create a copy of the Active Directory domain database in order to steal credential information, as well as obtain other information about domain members such as devices, users, and access rights.
attack.mitre.org →
T1003.004 LSA Secrets Credential Access
Adversaries with SYSTEM access to a host may attempt to access Local Security Authority (LSA) secrets, which can contain a variety of different credential materials, such as credentials for service accounts.
attack.mitre.org →
T1003.006 DCSync Credential Access
Adversaries may attempt to access credentials and other sensitive information by abusing a Windows Domain Controller's application programming interface (API)(Citation: Microsoft DRSR Dec 2017) (Citation: Microsoft GetNCCChanges) (Citati…
attack.mitre.org →
T1003.008 /etc/passwd and /etc/shadow Credential Access
Adversaries may attempt to dump the contents of <code>/etc/passwd</code> and <code>/etc/shadow</code> to enable offline password cracking.
attack.mitre.org →
T1010 Application Window Discovery Discovery
Adversaries may attempt to get a listing of open application windows.
attack.mitre.org →
T1012 Query Registry Discovery
Adversaries may interact with the Windows Registry to gather information about the system, configuration, and installed software.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2023-39745Same product: Tp-Link Tl-Wr841N V8
CVE-2024-25139Same vendor: Tp-Link
CVE-2025-25900Same vendor: Tp-Link
CVE-2024-48714Same vendor: Tp-Link
CVE-2023-36359Same vendor: Tp-Link
CVE-2023-36358Same vendor: Tp-Link
CVE-2023-36355Same vendor: Tp-Link
CVE-2024-54887Same vendor: Tp-Link
CVE-2024-48710Same vendor: Tp-Link
CVE-2023-30383Same vendor: Tp-Link

Affected Assets

tp-link
tl-wr940n v2 firmware
all versions
tp-link
tl-wr941nd v5 firmware
all versions
tp-link
tl-wr841n v8 firmware
all versions

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.

ID.RA-01 partial match
blocks

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

PR.PS-02 partial match
blocks

Routine patching replaces vulnerable code containing unchecked buffer copies with corrected versions.

PR.PS-06 partial match
blocks

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

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.5.14 Information transfer partial match
removes
A.5.15 Access control partial match
removes
A.5.16 Identity management partial match
removes
A.5.17 Authentication information partial match
removes
A.5.18 Access rights partial match
removes
A.8.10 Information deletion partial match
removes

References