VulnerabilityPublished 25 Feb 2026

CVE-2026-27846: Linksys MR9600 · Missing Authentication

Affects Linksys MR9600Source CVE Database V5

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Not known to be exploited · CVSS 6.2 Medium.

Data as of 29 Oct 2026, 19:04 UTC

CVSS 3.1 base score

6.2Medium

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

EPSS: 0.1% chance of exploitation in 30 days – higher than 4% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

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

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

Attack Vector: Local: The vulnerable component is not bound to the network stack and the attacker’s path is via read/write/execute capabilities. Either: the attacker exploits the vulnerability by accessing the target system locally (e.g., keyboard, console), or remotely (e.g., SSH); or the attacker relies on User Interaction by another person to perform actions required to exploit the vulnerability (e.g., tricking a legitimate user into opening a malicious document).
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: None: There is no loss of integrity within 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 25 Feb 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 29 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.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), 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

Affected software

Product	Affected	Fixed in
LinksysMR9600	Affected =1.0.4.205530	Fixed in–
LinksysMX4200	Affected =1.0.13.210200	Fixed in–

AI-suggested

Enforce strict physical security controls around networking equipment to prevent unauthorized access to the devices.
Monitor mesh network configurations regularly for unauthorized additions or changes.
Disable mesh functionality if not required or restrict mesh device additions through administrative controls if supported.
Change default administrator and Wi-Fi passwords to strong, unique credentials to limit the impact if credentials are exposed.
Implement network segmentation to isolate critical systems from potentially compromised network segments.
Stay informed about firmware updates from Linksys and apply patches promptly once available.
Use tamper-evident seals or enclosures on devices to detect physical interference.
Conduct periodic security audits and penetration tests focusing on physical and network access controls. These steps go beyond generic advice by emphasizing physical security, configuration monitoring, and proactive network design to mitigate risks from this vulnerability.

Description

Due to missing authentication, a user with physical access to the device can misuse the mesh functionality for adding a new mesh device to the network to gain access to sensitive information, including the password for admin access to the web interface and the Wi-Fi passwords.This issue affects MR9600: 1.0.4.205530; MX4200: 1.0.13.210200.

Impact

The primary impact of CVE-2026-27846 is the compromise of confidentiality of sensitive credentials, including admin and Wi-Fi passwords, which can lead to unauthorized network access. Attackers gaining these credentials can manipulate network configurations, intercept or redirect traffic, and potentially launch further attacks against internal systems. While integrity and availability are not directly affected, the breach of credentials undermines overall network security posture. Organizations relying on Linksys MR9600 and MX4200 routers in sensitive environments, such as corporate offices, government agencies, or critical infrastructure, face increased risk of insider threats or physical tampering. The requirement for physical access limits remote exploitation but does not eliminate risk in environments with shared or poorly secured facilities. The lack of known exploits reduces immediate threat but also indicates a need for proactive mitigation before attackers develop tools to exploit this vulnerability.

CWE-306Missing Authentication for Critical Functionality (opens in a new tab)
Base weaknessLikelihood of exploit: HighCWE Top 25 (2025): #21OWASP Top 10 A07:2025: Authentication Failures (opens in a new tab)
The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources.
Architecture and Design
Divide the software into anonymous, normal, privileged, and administrative areas. Identify which of these areas require a proven user identity, and use a centralized authentication capability.
Architecture and Design
For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks…
Architecture and Design
Where possible, avoid implementing custom, "grow-your-own" authentication routines and consider using authentication capabilities as provided by the surrounding framework, operating system, or environment.
OWASP Cheat Sheets
OWASP Authentication (opens in a new tab)
OWASP ASVS 4.0.3
V1.2.3 (opens in a new tab)
V1.2.2 (opens in a new tab)
V1.2.4 (opens in a new tab)
Attack patterns
Choosing Message Identifier (opens in a new tab)
Force the System to Reset Values (opens in a new tab)
Using Unpublished Interfaces or Functionality (opens in a new tab)
Cross Site Request Forgery (opens in a new tab)
Communication Channel Manipulation (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

syss.de/fileadmin/dokumente/Publikationen/Advisories/SYSS-2025-002.txt (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 4 Mar 2026, 23:08 UTC

WeaknessesCWE-306

Technical details

References

Community reviews

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