CVE-2025-9935VulnerabilityPublished 3 Sep 2025

CVE-2025-9935: TOTOLINK N600R · Command Injection

Affects TOTOLINK N600RSource CVE Database V5

Not known to be exploited · CVSS 6.9 Medium.

Data as of 26 Oct 2026, 08:30 UTC

CVSS 4.0 base score

6.9Medium

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

EPSS: 2.7% chance of exploitation in 30 days – higher than 85% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P

Base metrics

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: None
User Interaction: None
Vulnerable system confidentiality: Low
Vulnerable system integrity: Low
Vulnerable system availability: Low
Subsequent system confidentiality: None
Subsequent system integrity: None
Subsequent system availability: None

Threat metrics

Exploit Maturity: POC

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

Attack Vector: Network: The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, 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: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the Vulnerable System.
Vulnerable system integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact to the Vulnerable System.
Vulnerable system availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the Vulnerable System are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the Vulnerable System.
Subsequent system confidentiality: None: There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.
Exploit Maturity: POC: Based on threat intelligence sources each of the following must apply: · Proof-of-concept is publicly available · No knowledge of reported attempts to exploit this vulnerability · No knowledge of publicly available solutions used to simplify attempts to exploit the vulnerability

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 3 Sep 2025
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 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

Organizations should immediately verify if they deploy TOTOLINK N600R routers with the affected firmware version 4.3.0cu.7866_B20220506. Network administrators should restrict access to the router’s web management interface by implementing network segmentation and firewall rules to limit access only to trusted internal IP addresses. Disabling remote management features or changing default management ports can reduce exposure. Monitoring network traffic for unusual requests to /web_cste/cgi-bin/cstecgi.cgi and implementing intrusion detection/prevention systems (IDS/IPS) with signatures for this vulnerability can help detect exploitation attempts. Additionally, organizations should conduct regular vulnerability assessments and penetration tests to identify exposed devices and validate mitigation effectiveness. Educating IT staff about this vulnerability and maintaining an inventory of network devices will aid in rapid response and remediation.

Description

A vulnerability was determined in TOTOLINK N600R 4.3.0cu.7866_B20220506. This vulnerability affects the function sub_4159F8 of the file /web_cste/cgi-bin/cstecgi.cgi. Executing manipulation can lead to command injection. The attack can be executed remotely. The exploit has been publicly disclosed and may be utilized.

Impact

For European organizations, this vulnerability poses a tangible risk to network security and operational continuity. TOTOLINK routers, including the N600R model, are used in various small to medium business environments and residential settings across Europe. Successful exploitation could lead to unauthorized access to network traffic, disruption of internet connectivity, or use of compromised routers as a foothold for further attacks within corporate networks. This is particularly concerning for organizations with remote or branch offices relying on these devices for internet access or VPN termination. Confidentiality could be compromised through interception or manipulation of data, while integrity and availability of network services could be degraded or lost. The medium severity rating suggests moderate impact, but the ease of exploitation and lack of authentication requirement elevate the threat level. European entities in sectors such as finance, healthcare, and critical infrastructure, where network reliability and data protection are paramount, could face operational and reputational damage if targeted.

References

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Exploitation evidence

What to do

Description

AI analysisMachine-generated, updated 3 Sep 2025, 23:32 UTC

Technical details

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