CVE-2025-59449VulnerabilityPublished 6 Oct 2025Updated 26 Nov 2025

CVE-2025-59449: YoSmart YoLink MQTT broker · Incorrect Authorization

Affects YoSmart YoLink MQTT brokerSource CVE Database V5

Not known to be exploited · CVSS 4.9 Medium.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 3.1 base score

4.9Medium

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

EPSS: 0.2% chance of exploitation in 30 days – higher than 20% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

Attack Vector: Network
Attack Complexity: High
Privileges Required: Low
User Interaction: None
Scope: Changed
Confidentiality: Low
Integrity: Low
Availability: None

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

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, 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: High: A successful attack depends on conditions beyond the attacker's control. That is, a successful attack cannot be accomplished at will, but requires the attacker to invest in some measurable amount of effort in preparation or execution against the vulnerable component before a successful attack can be expected. For example, a successful attack may require an attacker to: gather knowledge about the environment in which the vulnerable target/component exists; prepare the target environment to improve exploit reliability; or inject themselves into the logical network path between the target and the resource requested by the victim in order to read and/or modify network communications (e.g., a man in the middle attack).
Privileges Required: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
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 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 6 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
YoSmart YoLink MQTT broker	Affected =0	Fixed in–

AI-suggested

1. Network Segmentation: Isolate the YoLink MQTT broker and associated IoT devices on dedicated network segments with strict access controls to limit exposure to untrusted networks. 2. Access Control: Implement firewall rules to restrict inbound and outbound MQTT traffic to known, authorized IP addresses and devices. 3. Device ID Management: Where possible, randomize or obfuscate device IDs to reduce predictability and enumeration risk. 4. Monitoring and Logging: Deploy anomaly detection systems to monitor MQTT traffic for unusual commands or access patterns indicative of cross-account attacks. 5. Vendor Engagement: Urge YoSmart to release patches that enforce robust authorization checks and improve device ID generation mechanisms. 6. Incident Response: Prepare response plans for potential device compromise, including device reset and credential rotation. 7. User Awareness: Educate users on the risks of sharing device IDs and the importance of securing network access to IoT devices. 8. Firmware Updates: Regularly check for and apply vendor updates once available to remediate the vulnerability. 9. Alternative Solutions: Evaluate alternative IoT platforms with stronger built-in security controls if patching is delayed.

Description

The YoSmart YoLink MQTT broker through 2025-10-02 does not enforce sufficient authorization controls to prevent cross-account attacks, allowing an attacker to remotely operate affected devices if the attacker obtains the associated device IDs. Because YoLink device IDs are predictable, an attacker can exploit this to gain full control over any other YoLink user's devices.

Impact

For European organizations, the vulnerability could lead to unauthorized remote control of IoT devices, impacting privacy, operational integrity, and potentially safety depending on device function. Confidentiality is compromised as attackers can access device states and control commands. Integrity is affected since attackers can manipulate device behavior, potentially causing incorrect operations or disruptions. Although availability is not directly impacted, indirect effects such as operational disruptions or safety incidents could occur. Organizations relying on YoLink devices for smart building management, industrial automation, or home automation are particularly at risk. The cross-account nature of the attack means that even users with properly secured accounts could have their devices compromised if device IDs are predictable. This could lead to data leakage, unauthorized surveillance, or sabotage of critical IoT infrastructure. The medium CVSS score reflects moderate ease of exploitation but significant potential impact on confidentiality and integrity.

CWE-863Incorrect Authorization (opens in a new tab)
Class weaknessLikelihood of exploit: HighCWE Top 25 (2025): #17OWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.
Architecture and Design
Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) to enforce the roles at the appropriate boundaries.
Architecture and Design
Ensure that access control checks are performed related to the business logic. These checks may be different than the access control checks that are applied to more generic resources such as files, connections, processes, memory, and database records.
Architecture and Design · Libraries or Frameworks
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
OWASP Cheat Sheets
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V8.3.8 (opens in a new tab)
V13.4.2 (opens in a new tab)
V7.2.2 (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 26 Nov 2025, 16:29 UTC

WeaknessesCWE-863

Technical details

References

Community reviews

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