CVE-2025-67188
Memory Safety in Totolink A950Rg Firmware 4.1.2cu.5204_b20210112
Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HSummary
CVE-2025-67188 is a critical-severity Classic Buffer Overflow (CWE-120) 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 47th 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-2025-67188 Vulnerability Summary**
CVE-2025-67188 is a stack-based buffer overflow vulnerability in the TOTOLINK A950RG router running firmware version V4.1.2cu.5204_B20210112. The flaw resides in the `setRadvdCfg` interface of the `/lib/cste_modules/ipv6.so` module, where insufficient validation of the user-supplied `radvdinterfacename` parameter length allows overflow of a fixed-size stack buffer (CWE-120). Published on 2026-02-03 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), it poses a critical risk due to its simplicity and impact.
Unauthenticated remote attackers can exploit this over the network by sending a crafted HTTP request to the vulnerable endpoint, triggering the overflow without user interaction. Successful exploitation enables arbitrary code execution with root privileges on the device, potentially allowing full compromise, data exfiltration, persistent backdoor installation, or use as a pivot in larger network attacks.
The referenced GitHub advisory (https://github.com/SunnyYANGyaya/cuicuishark-sheep-fishIOT/blob/main/ToTolink/A950RG/5024-ipv6-setRadvdCfg-radvdinterfacename-buffer.md) provides proof-of-concept details, including vulnerable code snippets and exploit reproduction steps, but no vendor patches are mentioned. Security practitioners should immediately isolate affected devices, monitor for anomalous traffic to the web interface, and check for firmware updates from TOTOLINK; input sanitization or disabling the IPv6 module may serve as interim mitigations. No evidence of in-the-wild exploitation has been reported.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2025-206713
Vulnerability Data
A buffer overflow vulnerability exists in TOTOLINK A950RG V4.1.2cu.5204_B20210112. The issue resides in the setRadvdCfg interface of the /lib/cste_modules/ipv6.so module. The function fails to properly validate the length of the user-controlled radvdinterfacename parameter, allowing remote attackers to trigger a stack…
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buffer overflow.
- 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.