VulnerabilityPublished 3 Feb 2026Updated 5 Feb 2026

CVE-2025-67188: TOTOLINK A950RG · Classic Buffer Overflow

Source CVE Database V5

Not known to be exploited · CVSS 9.8 Critical.

Data as of 26 Oct 2026, 10:12 UTC

CVSS 3.1 base score

9.8Critical

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.6% chance of exploitation in 30 days – higher than 52% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: High
Availability: High

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 3 Feb 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

AI-suggested

Immediate action should be to check for and apply any available firmware updates from TOTOLINK addressing this vulnerability. Monitor vendor communications closely for patches.
If patches are unavailable, restrict network access to the router’s management interfaces, especially the setRadvdCfg interface, by implementing firewall rules or network segmentation to limit exposure to untrusted networks.
Disable IPv6 routing or the radvd service if not required, reducing the attack surface related to the vulnerable module.
Employ network intrusion detection/prevention systems (IDS/IPS) with signatures or anomaly detection to identify and block attempts to exploit this buffer overflow.
Conduct regular network scans to identify devices running vulnerable firmware versions and prioritize their remediation.
Implement strict access controls and monitoring on network devices to detect unusual activity indicative of exploitation attempts.
Educate IT staff about this vulnerability and ensure incident response plans include scenarios involving router compromise.
Consider deploying network-level mitigations such as VPNs or zero-trust architectures to reduce reliance on potentially vulnerable edge devices. These steps go beyond generic advice by focusing on specific controls related to the vulnerable interface and router model.

Description

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 buffer overflow.

Impact

For European organizations, the impact of CVE-2025-67188 is significant. The TOTOLINK A950RG router is used in various enterprise and residential environments, including small businesses and potentially critical infrastructure sectors. Exploitation can lead to complete device takeover, allowing attackers to intercept, modify, or disrupt network traffic, exfiltrate sensitive data, or use the compromised device as a foothold for further attacks within the network. This threatens the confidentiality, integrity, and availability of organizational data and services. In sectors such as finance, healthcare, and government, where data sensitivity and uptime are paramount, the consequences could be severe, including regulatory penalties under GDPR for data breaches. Additionally, compromised routers can be leveraged in botnets or to launch distributed denial-of-service (DDoS) attacks, amplifying the threat landscape. The lack of authentication and user interaction requirements lowers the barrier for exploitation, increasing the likelihood of attacks. The absence of known public exploits currently provides a window for mitigation, but also means organizations must act proactively to prevent future incidents.

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') (opens in a new tab)
Base weaknessLikelihood of exploit: HighCWE Top 25 (2025): #11
The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer.
Requirements · Language Selection
Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Architecture and Design · Libraries or Frameworks
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Operation · Build and Compilation · Environment Hardening
Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index…
OWASP Cheat Sheets
Docker Security (opens in a new tab)
XML Security (opens in a new tab)
OWASP ASVS 4.0.3
V5.4.1 (opens in a new tab)
V14.1.2 (opens in a new tab)
V13.3.1 (opens in a new tab)
Attack patterns
Buffer Overflow via Environment Variables (opens in a new tab)
Overflow Buffers (opens in a new tab)
Client-side Injection-induced Buffer Overflow (opens in a new tab)
Filter Failure through Buffer Overflow (opens in a new tab)
MIME Conversion (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

github.com/SunnyYANGyaya/cuicuishark-sheep-fishIOT/blob/main/ToTolink/A950RG/5024-ipv6-setRadvdCfg-radvdinterfacename-buffer.md (opens in a new tab)

Community reviews

Loading reviews…

Exploitation evidence

What to do

Description

AI analysisMachine-generated, updated 11 Feb 2026, 11:38 UTC

WeaknessesCWE-120

Technical details

References

Community reviews

Related threats