CVE-2025-62413VulnerabilityPublished 16 Oct 2025

CVE-2025-62413: emqx MQTTX · Cross-site Scripting

Affects emqx MQTTXSource CVE Database V5

Not known to be exploited · CVSS 6.1 Medium · fixed in 1.12.1 : update emqx MQTTX when convenient.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 3.1 base score

6.1Medium

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

EPSS: 0.3% chance of exploitation in 30 days – higher than 25% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 1.12.1

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: Required
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: 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: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
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 16 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
GitHubemqx/MQTTX`pkg:github/emqx/MQTTX`Other threats	Affected =1.12.0	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

European organizations should immediately upgrade MQTTX clients from version 1.12.0 to 1.12.1 or later to remediate this vulnerability. Until upgrading is possible, users should avoid opening or viewing MQTT messages from untrusted or unknown sources within MQTTX. Network segmentation should be enforced to isolate MQTT testing environments from production systems, limiting exposure to malicious payloads. Employing MQTT brokers with strict message validation and filtering can reduce the risk of malicious payload injection. Additionally, organizations should monitor MQTT client logs for unusual activities and consider implementing endpoint security controls that detect script execution anomalies within client applications. Training users to recognize suspicious MQTT messages and restricting MQTTX usage to trusted personnel can further reduce risk. Finally, integrating MQTT traffic monitoring and anomaly detection tools can help identify exploitation attempts early.

Description

MQTTX is an MQTT 5.0 desktop client and MQTT testing tool. A Cross-Site Scripting (XSS) vulnerability was introduced in MQTTX v1.12.0 due to improper handling of MQTT message payload rendering. Malicious payloads containing HTML or JavaScript could be rendered directly in the MQTTX message viewer. If exploited, this could allow attackers to execute arbitrary scripts in the context of the application UI — for example, attempting to access MQTT connection credentials or trigger unintended actions through script injection. This vulnerability is especially relevant when MQTTX is used with brokers in untrusted or multi-tenant environments, where message content cannot be fully controlled. This vulnerability is fixed in 1.12.1.

Impact

For European organizations, this vulnerability poses a risk primarily to those using MQTTX 1.12.0 for MQTT testing or client operations, especially in sectors relying on IoT infrastructure, smart manufacturing, or connected services. Exploitation could lead to leakage of MQTT credentials, enabling attackers to intercept or manipulate MQTT traffic, potentially disrupting critical IoT communications or gaining further network footholds. This could impact confidentiality and integrity of data transmitted via MQTT. Organizations operating in multi-tenant or cloud-based MQTT broker environments are at higher risk, as malicious actors could inject payloads to exploit this vulnerability. While the vulnerability does not directly affect availability, the indirect consequences of compromised MQTT sessions could lead to operational disruptions. The medium severity rating reflects the need for user interaction and the limited scope of impact to the MQTTX client, but the potential for lateral movement or data exposure in sensitive IoT deployments elevates the concern for European critical infrastructure and industrial sectors.

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (opens in a new tab)
Base weaknessLikelihood of exploit: HighCWE Top 25 (2025): #1OWASP Top 10 A05:2025: Injection (opens in a new tab)
The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.
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.
Implementation · Architecture and Design
Understand the context in which your data will be used and the encoding that will be expected. This is especially important when transmitting data between different components, or when generating outputs that can contain multiple encodings at the same time, such as web pages or multi-part mail messages.
Architecture and Design · Implementation · Attack Surface Reduction
Understand all the potential areas where untrusted inputs can enter your software: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any external systems that provide…
OWASP Cheat Sheets
Cross Site Scripting Prevention (opens in a new tab)
DOM based XSS Prevention (opens in a new tab)
Injection Prevention (opens in a new tab)
Abuse Case (opens in a new tab)
Deserialization (opens in a new tab)
OWASP ASVS 4.0.3
V5.3.3 (opens in a new tab)
V1.5.1 (opens in a new tab)
Attack patterns
XSS Using MIME Type Mismatch (opens in a new tab)
DOM-Based XSS (opens in a new tab)
Reflected XSS (opens in a new tab)
Stored XSS (opens in a new tab)
Cross-Site Scripting (XSS) (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 16 Oct 2025, 18:29 UTC

WeaknessesCWE-79

Technical details

References

Community reviews

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