CVE-2025-7882VulnerabilityPublished 20 Jul 2025Updated 21 Jul 2025

CVE-2025-7882: Mercusys MW301R · Improper Restriction of Excessive Authentication Attempts

Affects Mercusys MW301RSource CVE Database V5

Not known to be exploited · CVSS 2.3 Low.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 4.0 base score

2.3Low

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:A/AC:H/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P

Base metrics

Attack Vector: Adjacent
Attack Complexity: High
Attack Requirements: None
Privileges Required: None
User Interaction: None
Vulnerable system confidentiality: None
Vulnerable system integrity: Low
Vulnerable system availability: None
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: Adjacent: The vulnerable system is bound to a protocol stack, but the attack is limited at the protocol level to a logically adjacent topology. This can mean an attack must be launched from the same shared proximity (e.g., Bluetooth, NFC, or IEEE 802.11) or logical network (e.g., local IP subnet), or from within a secure or otherwise limited administrative domain (e.g., MPLS, secure VPN within an administrative network zone).
Attack Complexity: High: The successful attack depends on the evasion or circumvention of security-enhancing techniques in place that would otherwise hinder the attack. These include: Evasion of exploit mitigation techniques, for example, circumvention of address space randomization (ASLR) or data execution prevention (DEP) must be performed for the attack to be successful; Obtaining target-specific secrets. The attacker must gather some target-specific secret before the attack can be successful. A secret is any piece of information that cannot be obtained through any amount of reconnaissance. To obtain the secret the attacker must perform additional attacks or break otherwise secure measures (e.g. knowledge of a secret key may be needed to break a crypto channel). This operation must be performed for each attacked target.
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: None: There is no loss of confidentiality within 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: None: There is no impact to availability within 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 20 Jul 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

AI-suggested

Given the absence of official patches, European organizations should implement specific mitigations: 1) Restrict physical and network access to the local network segments where Mercusys MW301R routers are deployed, limiting exposure to trusted personnel only. 2) Implement strong network segmentation to isolate vulnerable devices from critical infrastructure and sensitive data. 3) Monitor network traffic for unusual authentication attempts or brute-force patterns targeting router management interfaces. 4) Change default credentials immediately and enforce strong, unique passwords for router administration. 5) Disable remote management features if enabled, to reduce attack surface. 6) Consider replacing Mercusys MW301R devices with more secure alternatives that receive timely security updates. 7) Employ network access control (NAC) solutions to prevent unauthorized devices from connecting to the local network. 8) Regularly audit router configurations and logs to detect suspicious activities early. These measures go beyond generic advice by focusing on network architecture and operational controls tailored to the specific vulnerability context.

Description

A vulnerability was found in Mercusys MW301R 1.0.2 Build 190726 Rel.59423n. It has been rated as problematic. This issue affects some unknown processing of the component Login. The manipulation leads to improper restriction of excessive authentication attempts. The attack can only be initiated within the local network. The complexity of an attack is rather high. The exploitation is known to be difficult. The exploit has been disclosed to the public and may be used. The vendor was contacted early about this disclosure but did not respond in any way.

Impact

For European organizations, the impact of this vulnerability is generally limited but still noteworthy. Since the vulnerability requires local network access, it primarily threatens internal network security rather than remote attackers. In environments where Mercusys MW301R routers are deployed, an insider threat or an attacker who has gained initial foothold inside the network could leverage this flaw to escalate privileges by brute forcing router credentials. This could lead to unauthorized changes in network configurations, interception of internal traffic, or pivoting to other internal systems. Small and medium-sized enterprises (SMEs) or home office setups using this router model may be more vulnerable due to less mature network segmentation and monitoring. Larger organizations with robust network segmentation and monitoring are less likely to be affected. The lack of vendor response and patches increases the risk for organizations that rely on this hardware. Additionally, the vulnerability could be exploited in targeted attacks against organizations in sectors where Mercusys devices are common, potentially disrupting internal network management or enabling further lateral movement by attackers.

References

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Exploitation evidence

What to do

Description

AI analysisMachine-generated, updated 28 Jul 2025, 01:03 UTC

Technical details

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