CVE-2025-66454VulnerabilityPublished 2 Dec 2025

CVE-2025-66454: ArcadeAI arcade-mcp · Use of Hard-coded Cryptographic Key

Affects ArcadeAI arcade-mcpSource CVE Database V5

Not known to be exploited · CVSS 6.5 Medium : upgrade to 1.5.4 when convenient.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 3.1 base score

6.5Medium

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

EPSS: 0.3% chance of exploitation in 30 days – higher than 23% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 1.5.4

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
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: 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: 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 2 Dec 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

Upgrade arcadeai/arcade-mcp to 1.5.4.

Affected software

Product	Affected	Fixed in
GitHubarcadeai/arcade-mcp`pkg:github/arcadeai/arcade-mcp`Other threats	Affected <1.5.4	Fixed in 1.5.4

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 verify if they are running arcade-mcp versions earlier than 1.5.4. The primary mitigation is to upgrade all affected instances to version 1.5.4 or later, where the hardcoded secret is removed or properly secured. If upgrading is not immediately possible, organizations should restrict network access to arcade-mcp servers by implementing strict firewall rules, allowing only trusted internal IP addresses to connect. Additionally, monitoring and logging of all authentication attempts and tool invocations should be enhanced to detect suspicious activity indicative of JWT forgery or unauthorized access. Organizations should also consider implementing additional layers of authentication or API gateway protections in front of arcade-mcp endpoints. Regular security audits and code reviews should be conducted to identify any other hardcoded secrets or similar cryptographic weaknesses. Finally, educating developers and administrators about the risks of hardcoded credentials and enforcing secure key management practices will help prevent similar vulnerabilities.

Description

CVE-2025-66454 is a medium severity vulnerability in ArcadeAI's arcade-mcp HTTP server versions prior to 1.5.4. The server uses a hardcoded default worker secret key "dev" that is never validated or overridden during startup. This allows unauthenticated attackers who know the default key to forge valid JWT tokens, bypassing FastAPI authentication entirely. Exploitation grants remote access to all worker endpoints, including tool enumeration and invocation, without any credentials. The vulnerability does not require user interaction or privileges and is exploitable over the network. It is fixed in version 1.5.4.

Impact

For European organizations using arcade-mcp versions prior to 1.5.4, this vulnerability poses a significant risk. Attackers can remotely bypass authentication and gain unauthorized access to internal tools and services managed by the arcade-mcp server. This can lead to unauthorized data access, manipulation, and potential disruption of services relying on these tools. Confidentiality is compromised as sensitive information about available tools and their functions can be enumerated and exploited. Integrity is at risk since attackers can invoke tools remotely, potentially altering system states or data. Although availability impact is not directly indicated, unauthorized tool invocation could lead to service disruptions. Given the ease of exploitation without authentication or user interaction, attackers can rapidly compromise vulnerable systems. This risk is heightened in environments where arcade-mcp servers are exposed to untrusted networks or the internet. European organizations in sectors such as gaming, software development, or any industry leveraging ArcadeAI’s platform could face operational and reputational damage if exploited.

CWE-321Use of Hard-coded Cryptographic Key (opens in a new tab)
Variant weaknessLikelihood of exploit: HighOWASP Top 10 A04:2025: Cryptographic Failures (opens in a new tab)
The product uses a hard-coded, unchangeable cryptographic key.
Architecture and Design
Prevention schemes mirror that of hard-coded password storage.
OWASP Cheat Sheets
Transport Layer Protection (opens in a new tab)
User Privacy Protection (opens in a new tab)
Password Storage (opens in a new tab)
Cryptographic Storage (opens in a new tab)
HSTS (opens in a new tab)
OWASP ASVS 4.0.3
V2.3.1 (opens in a new tab)
V2.6.2 (opens in a new tab)
V2.8.5 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-798Use of Hard-coded Credentials (opens in a new tab)
Base weaknessLikelihood of exploit: HighOWASP Top 10 A07:2025: Authentication Failures (opens in a new tab)
The product contains hard-coded credentials, such as a password or cryptographic key.
Architecture and Design
For outbound authentication: store passwords, keys, and other credentials outside of the code in a strongly-protected, encrypted configuration file or database that is protected from access by all outsiders, including other local users on the same system. Properly protect the key (CWE-320).
Architecture and Design
For inbound authentication: Rather than hard-code a default username and password, key, or other authentication credentials for first time logins, utilize a "first login" mode that requires the user to enter a unique strong password or key.
Architecture and Design
If the product must contain hard-coded credentials or they cannot be removed, perform access control checks and limit which entities can access the feature that requires the hard-coded credentials. For example, a feature might only be enabled through the system console instead of through a network connection.
OWASP Cheat Sheets
Key Management (opens in a new tab)
REST Security (opens in a new tab)
JSON Web Token for Java (opens in a new tab)
OWASP Authentication (opens in a new tab)
OWASP ASVS 4.0.3
V2.10.4 (opens in a new tab)
V6.4.1 (opens in a new tab)
V3.5.2 (opens in a new tab)
Attack patterns
Read Sensitive Constants Within an Executable (opens in a new tab)
Try Common or Default Usernames and Passwords (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

Loading reviews…

Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 9 Dec 2025, 19:11 UTC

WeaknessesCWE-321, CWE-798

Technical details

References

Community reviews

Related threats