VulnerabilityPublished 6 Nov 2025Updated 26 Feb 2026

CVE-2025-12790: Nicholas J Humfrey ruby-mqtt · Path Traversal: '..filename

Affects Nicholas J Humfrey ruby-mqttSource CVE Database V5

Not known to be exploited · CVSS 7.4 High.

Data as of 26 Oct 2026, 15:59 UTC

CVSS 3.1 base score

7.4High

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

EPSS: 0.3% chance of exploitation in 30 days – higher than 31% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

Attack Vector: Network
Attack Complexity: High
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: High
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: 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: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to 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 Nov 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 26 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.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, 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
RubyGemsmqtt`pkg:gem/mqtt`Other threats	Affected =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

Organizations should immediately audit their use of the ruby-mqtt library and verify if hostname validation is enabled or can be enforced. If the library version in use lacks this feature, consider upgrading to a patched version once available or applying custom patches to enforce strict hostname verification during TLS handshakes. Network-level mitigations include deploying MQTT brokers and clients within secure, segmented networks to reduce exposure to MITM attacks. Employing VPNs or secure tunnels for MQTT traffic can add an additional layer of protection. Monitoring network traffic for anomalies and implementing intrusion detection systems focused on MQTT protocol anomalies can help detect exploitation attempts. Developers should follow secure coding practices by validating all TLS parameters and avoid disabling certificate checks. Finally, maintain awareness of updates from the ruby-mqtt project and apply security patches promptly when released.

Description

A flaw was found in Rubygem MQTT. By default, the package used to not have hostname validation, resulting in possible Man-in-the-Middle (MITM) attack.

Impact

The primary impact of this vulnerability is the potential for attackers to intercept and manipulate MQTT traffic, leading to unauthorized disclosure of sensitive information and data tampering. This can compromise the confidentiality and integrity of communications in IoT devices, industrial control systems, and messaging platforms relying on ruby-mqtt. Exploitation could allow attackers to inject malicious commands, disrupt device operations, or exfiltrate data, potentially causing operational disruptions and privacy breaches. Given MQTT's widespread adoption in critical infrastructure and consumer IoT, the vulnerability could have far-reaching consequences, including undermining trust in connected systems and causing financial and reputational damage to affected organizations. The absence of authentication requirements and user interaction lowers the barrier for exploitation, increasing the risk profile. However, the high attack complexity and requirement for network access somewhat limit the exploitability to attackers with network proximity or control.

References

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