VulnerabilityPublished 6 Nov 2025

CVE-2025-12790: MQTT does not validate hostnames

Affects mqttSource GCVE Database

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Authoritative record:CVE-2025-12790· High 7.4

Not known to be exploited · CVSS 7.4 High : upgrade to 0.7.0 soon.

Data as of 4 Nov 2026, 18:38 UTC

CVSS 3.1 base score

7.4High

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

Patch: Available – fixed in 0.7.0

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
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 4 Nov 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

Upgrade mqtt to 0.7.0.

Affected software

Product	Affected	Fixed in
RubyGemsmqtt	Affected <0.7.0	Fixed in 0.7.0

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

AI-suggested

A fix is available in Rubygem MQTT version 0.7.0. Users should upgrade to version 0.7.0 or later to remediate this vulnerability. Red Hat notes that no effective mitigation other than upgrading currently meets their criteria for ease of use and deployment. In environments where MQTT is used locally (e.g., Red Hat Satellite), the impact is low.

Description

A vulnerability in the Rubygem MQTT package prior to version 0.7.0 allows for possible Man-in-the-Middle (MITM) attacks due to lack of hostname validation by default. This flaw could enable attackers to intercept or modify communications. The issue is fixed in version 0.7.0. Red Hat notes that in their Satellite product the impact is low because the MQTT gem is used only locally between components on the same machine. No known exploits are reported in the wild.

Impact

The vulnerability allows an attacker to perform Man-in-the-Middle attacks by exploiting the lack of hostname validation in MQTT connections, potentially compromising confidentiality and integrity of data transmitted via MQTT. However, the impact is product-dependent; for example, Red Hat Satellite uses MQTT only locally, reducing risk. There are no known active exploits in the wild.

Summary

CVE-2025-12790 is a vulnerability in the Rubygem MQTT package where hostname validation was not performed by default, enabling potential Man-in-the-Middle (MITM) attacks. This flaw affects versions prior to 0.7.0 and was addressed by adding hostname validation in version 0.7.0. The vulnerability has a CVSS v3.1 score of 7.4 (high severity) with network attack vector, high attack complexity, no privileges required, no user interaction, and impacts confidentiality and integrity. Red Hat's advisory highlights that the impact is low in their Satellite product due to local-only use of MQTT. No public exploits or in-the-wild exploitation are known.

CWE-29Path Traversal: '\..\filename' (opens in a new tab)
Variant weakness
The product uses external input to construct a pathname that should be within a restricted directory, but it does not properly neutralize '\..\filename' (leading backslash dot dot) sequences that can resolve to a location that is outside of that directory.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
Implementation · Input Validation
Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174).
OWASP ASVS 4.0.3
V12.3.1 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 4 Nov 2026, 18:38 UTC

WeaknessesCWE-29

Technical details

References

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