CVE-2025-8938VulnerabilityPublished 14 Aug 2025Updated 15 Aug 2025

CVE-2025-8938: TOTOLINK N350R · Backdoor

Affects TOTOLINK N350RSource CVE Database V5

Not known to be exploited · CVSS 5.3 Medium.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 4.0 base score

5.3Medium

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

EPSS: 0.3% chance of exploitation in 30 days – higher than 26% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/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: Low
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: Low: The attacker requires privileges that provide basic capabilities that are typically limited to settings and resources owned by a single low-privileged user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources.
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 14 Aug 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 2026-10-25.

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

Affected software

Product	Affected	Fixed in
TOTOLINK N350R	Affected =1.2.3-B20130826	Fixed in–

AI-suggested

1. Immediate mitigation should include disabling the Telnet service on the TOTOLINK N350R router if it is not required, as this service is the attack vector. 2. If disabling Telnet is not feasible, network administrators should restrict access to the router's management interface to trusted IP addresses or VLANs, ideally isolating it from the internet-facing network. 3. Monitor network traffic for unusual Telnet connection attempts or unexpected administrative access patterns. 4. 5. Consider replacing affected routers with models from vendors that provide timely security updates and have a stronger security posture. 6. Implement network segmentation to limit the impact of a compromised router on critical systems. 7. Educate users about the risks of using outdated or unsupported network devices and encourage regular firmware updates as part of security hygiene.

Description

A vulnerability was found in TOTOLINK N350R 1.2.3-B20130826. This issue affects the function formSysTel of the file /boafrm/formSysTel of the component Telnet Service. The manipulation of the argument TelEnabled leads to backdoor. The attack may be initiated remotely. The exploit has been disclosed to the public and may be used.

Impact

For European organizations, especially small businesses and home offices relying on TOTOLINK N350R routers, this vulnerability poses a risk of unauthorized remote access to network infrastructure. Exploitation could lead to interception of sensitive data, disruption of internet connectivity, or use of the compromised router as a foothold for lateral movement within the network. While the device is typically used in smaller scale environments, the impact on confidentiality and integrity of communications can be significant, particularly for remote workers or small enterprises handling sensitive information. Additionally, compromised routers could be enlisted in botnets or used to launch distributed denial-of-service (DDoS) attacks, indirectly affecting organizational operations. The medium severity rating suggests that while the threat is not critical, it should not be ignored, especially given the ease of remote exploitation without authentication or user interaction. European organizations with limited IT security resources may be particularly vulnerable if they have not updated or replaced affected devices.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 22 Aug 2025, 01:10 UTC

Technical details

References

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