Cyber Resilience

CVE-2025-67187

Memory Safety in Totolink A950Rg Firmware 4.1.2cu.5204_b20210112

Public PoCMemory Safety
Published
03 February 2026
Modified
10 February 2026
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 0.0044 36th percentile
Risk Priority 71 floored blend · peak EPSS

Summary

CVE-2025-67187 is a critical-severity Stack-based Buffer Overflow (CWE-121) vulnerability in Totolink A950Rg 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 36th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

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.

CVE-2025-67187 is a stack-based buffer overflow vulnerability (CWE-121) affecting the TOTOLINK A950RG router on firmware version V4.1.2cu.5204_B20210112. The flaw occurs in the setIpQosRules interface of the /lib/cste_modules/firewall.so library, where the comment parameter is not properly validated for length, enabling overflow conditions.

With a CVSS v3.1 base score of 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H), the vulnerability is exploitable by any unauthenticated attacker over the network with low complexity and no user interaction. Exploitation involves sending a crafted request with an oversized comment parameter, potentially leading to arbitrary code execution and full compromise of the affected device, including high impacts on confidentiality, integrity, and availability.

A technical analysis and proof-of-concept are detailed in the GitHub reference at https://github.com/SunnyYANGyaya/cuicuishark-sheep-fishIOT/blob/main/ToTolink/A950RG/5024-setIpQosRules-comment-buffer.md. No vendor advisories or patches are specified in the available information.

EU & UK References

Vulnerability Data

A stack-based buffer overflow vulnerability was identified in TOTOLINK A950RG V4.1.2cu.5204_B20210112. The flaw exists in the setIpQosRules interface of /lib/cste_modules/firewall.so where the comment parameter is not properly validated for length.

CWE(s)
CWE-121

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-2025-60699Same product: Totolink A950Rg
CVE-2025-45797Same product: Totolink A950Rg
CVE-2025-67188Same product: Totolink A950Rg
CVE-2025-67189Same product: Totolink A950Rg
CVE-2025-67186Same product: Totolink A950Rg
CVE-2025-28026Same product: Totolink A950Rg
CVE-2025-28027Same product: Totolink A950Rg
CVE-2025-28029Same product: Totolink A950Rg
CVE-2025-28032Same product: Totolink A950Rg
CVE-2025-28033Same product: Totolink A950Rg

Affected Assets

totolink
a950rg firmware
4.1.2cu.5204_b20210112

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)
  • 2 hardening rules · 2 OS baselines
Validate
Prove the fix (OWASP ASVS)

—

Mitigating Controls (NIST 800-53 r5) AI

SA-11 Developer Testing and Evaluation good match

Developer testing and analysis can discover stack-buffer overflows before deployment.

SI-10 Information Input Validation good match

Input validation directly stops untrusted data from exceeding stack buffer bounds.

SI-16 Memory Protection good match

Memory-protection mechanisms limit the ability to execute injected code after a stack overflow.

SA-8 Security and Privacy Engineering Principles partial match

Secure-engineering principles include bounds-checked coding and safe buffer handling that avoid introducing the flaw.

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 prevent introduction of stack buffer overflows.

ID.RA-01 partial match
prevents

Vulnerability scanning can discover stack buffer overflows but does not prevent their introduction.

PR.PS-02 partial match
prevents

Patching eliminates known instances of the weakness after discovery.

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 (fuzzing, static analysis) detects stack overflows before release.

A.8.25 Secure development life cycle partial match
prevents

Secure SDLC mandates buffer-safety practices that directly prevent stack overflows.

A.8.26 Application security requirements partial match
prevents

Application security requirements can specify buffer-size and input-validation rules.

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

Secure architecture principles include memory-safety and least-privilege stack usage.

A.8.28 Secure coding partial match
prevents

Secure coding standards explicitly forbid unsafe buffer handling that causes CWE-121.

A.8.32 Change management none match
none

Change-management gates can enforce security reviews that catch buffer issues.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).

Oracle Linux 8 (1 rule)
  • V-248594 OL 8 must implement address space layout randomization (ASLR) to protect its memory from unauthorized code execution. prevents CWE-121
Oracle Linux 9 (1 rule)
  • V-271452 OL 9 must use a Linux Security Module configured to enforce limits on system services. prevents CWE-121

References