VulnerabilityPublished 8 Apr 2026

CVE-2026-5302: CoolerControl coolercontrold · Permissive Cross-domain Policy with Untrusted Domains

Affects CoolerControl coolercontroldSource CVE Database V5

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Not known to be exploited · CVSS 6.3 Medium : upgrade to 4.0.0 when convenient.

Data as of 30 Oct 2026, 11:52 UTC

CVSS 3.1 base score

6.3Medium

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

EPSS: 0.2% chance of exploitation in 30 days – higher than 17% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 4.0.0

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

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

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: 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: 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: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the impacted component are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 8 Apr 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 30 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

Upgrade CoolerControl coolercontrold to 4.0.0.

Affected software

Product	Affected	Fixed in
CoolerControlcoolercontrold	Affected >=2.0.0 <4.0.0	Fixed in 4.0.0

AI-suggested

If you cannot patch yet, consider restricting or disabling CORS policies on the affected service to limit cross-origin requests to trusted domains only. Avoid visiting untrusted websites while using affected versions. No vendor advisory states that no action is required or that the issue is already mitigated.

Description

CVE-2026-5302 is a medium severity vulnerability in CoolerControl's coolercontrold version 2.0.0 and earlier, caused by a permissive Cross-Origin Resource Sharing (CORS) policy that allows unauthenticated remote attackers to read data and send commands via malicious websites. This misconfiguration falls under CWE-942, indicating overly permissive cross-domain policies involving untrusted domains. The vulnerability enables attackers to bypass same-origin policy restrictions, potentially leading to unauthorized information disclosure and command execution on the affected service.

Impact

Successful exploitation of this vulnerability can lead to unauthorized disclosure of data and unauthorized command execution on the affected coolercontrold service. Because the vulnerability allows cross-origin requests from untrusted domains, attackers can leverage malicious websites to perform actions as if they were legitimate users, potentially compromising confidentiality, integrity, and availability of the service. However, exploitation requires user interaction (e.g., visiting a malicious website). There are no known exploits in the wild at this time.

Summary

CVE-2026-5302 describes a CORS misconfiguration vulnerability in CoolerControl's coolercontrold product versions prior to 4.0.0, specifically affecting version 2.0.0. The permissive cross-domain policy allows unauthenticated remote attackers to interact with the service from malicious websites, enabling them to read sensitive data and issue commands. This vulnerability is categorized under CWE-942, which involves permissive cross-domain policies that trust unverified domains. The CVSS v3.1 base score is 6.3 (medium), reflecting network attack vector, low attack complexity, no privileges required, user interaction needed, and impacts on confidentiality, integrity, and availability.

CWE-942Permissive Cross-domain Security Policy with Untrusted Domains (opens in a new tab)
Variant weaknessOWASP Top 10 A02:2025: Security Misconfiguration (opens in a new tab)
The product uses a web-client protection mechanism such as a Content Security Policy (CSP) or cross-domain policy file, but the policy includes untrusted domains with which the web client is allowed to communicate.
Architecture and Design · Operation · Attack Surface Reduction
Define a restrictive Content Security Policy or cross-domain policy file.
Architecture and Design · Operation · Attack Surface Reduction
Avoid using wildcards in the CSP / cross-domain policy file. Any domain matching the wildcard expression will be implicitly trusted, and can perform two-way interaction with the target server.
Architecture and Design · Operation · Environment Hardening
For Flash, modify crossdomain.xml to use meta-policy options such as 'master-only' or 'none' to reduce the possibility of an attacker planting extraneous cross-domain policy files on a server.
OWASP ASVS 4.0.3
V8.3.8 (opens in a new tab)
V1.14.1 (opens in a new tab)
V13.4.2 (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 15 Apr 2026, 16:00 UTC

WeaknessesCWE-942

Technical details

References

Community reviews

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