CVE-2025-62773VulnerabilityPublished 22 Oct 2025

CVE-2025-62773: Mercku M6a · Hidden Functionality

Affects Mercku M6aSource CVE Database V5

Not known to be exploited · CVSS 2.4 Low.

Data as of 26 Oct 2026, 07:57 UTC

CVSS 3.1 base score

2.4Low

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

EPSS: 0.1% chance of exploitation in 30 days – higher than 6% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

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

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

Attack Vector: Adjacent: The vulnerable component is bound to the network 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 physical (e.g., Bluetooth or IEEE 802.11) or logical (e.g., local IP subnet) network, or from within a secure or otherwise limited administrative domain (e.g., MPLS, secure VPN to an administrative network zone).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: High: The attacker is authorized with (i.e., requires) privileges that provide significant (e.g., administrative) control over the vulnerable component that could affect component-wide settings and files.
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: None: There is no loss of confidentiality within the impacted component.
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 on the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 22 Oct 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 2026-10-26.

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
Mercku M6a	Affected =0	Fixed in–

AI-suggested

European organizations should implement strict access controls to limit administrative access to Mercku M6a devices, ensuring only trusted personnel can perform configuration changes. Network segmentation should be used to isolate management interfaces from general network traffic. Monitoring and alerting should be configured to detect any activation of TELNET services on these devices, including unusual router.telnet.enabled.update requests in logs or network traffic. Disable TELNET services if enabled, and prefer secure management protocols such as SSH. Regularly audit device configurations to ensure no hidden or undocumented features are active. Organizations should engage with Mercku for firmware updates and apply patches promptly once available. Additionally, consider deploying network intrusion detection systems (NIDS) to identify TELNET traffic and block unauthorized access attempts. Training administrators on the risks of hidden functionalities and secure configuration practices is also recommended.

Description

Mercku M6a devices through 2.1.0 allow TELNET sessions via a router.telnet.enabled.update request by an administrator.

Impact

For European organizations using Mercku M6a devices, this vulnerability could lead to inadvertent or malicious enabling of TELNET access on routers, which is inherently insecure. While the vulnerability does not directly compromise confidentiality or availability, enabling TELNET could allow attackers with network access to intercept or manipulate router communications if they gain access through other means. This could facilitate lateral movement or reconnaissance within corporate networks. The requirement for administrator privileges limits the risk to insider threats or attackers who have already compromised administrative credentials. Organizations in sectors with strict network security requirements, such as finance, healthcare, or critical infrastructure, may face compliance risks if insecure protocols like TELNET are enabled. The lack of patches means organizations must rely on configuration management and monitoring to mitigate risk until vendor updates are available.

CWE-912Hidden Functionality (opens in a new tab)
Class weakness
The product contains functionality that is not documented, not part of the specification, and not accessible through an interface or command sequence that is obvious to the product's users or administrators.
Installation
Always verify the integrity of the product that is being installed.
Attack patterns
Try All Common Switches (opens in a new tab)
Reverse Engineer an Executable to Expose Assumed Hidden Functionality (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 29 Oct 2025, 04:39 UTC

WeaknessesCWE-912

Technical details

References

Community reviews

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