VulnerabilityPublished 21 Aug 2025Updated 22 Aug 2025

CVE-2025-51606: hippo4j · Use of Hard-coded Credentials

Source CVE Database V5

Not known to be exploited · CVSS 8.8 High.

Data as of 26 Oct 2026, 15:59 UTC

CVSS 3.1 base score

8.8High

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

EPSS: 0.3% chance of exploitation in 30 days – higher than 28% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

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

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: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
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: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 21 Aug 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

AI-suggested

Immediate upgrade: Organizations should upgrade hippo4j to a version where this vulnerability is patched.
Secret key rotation: Replace the hard-coded secret key with a securely generated, environment-specific secret stored outside of source code and binaries, such as in environment variables or secure vaults.
Code audit: Conduct a thorough audit of the codebase and binaries to identify and remove any hard-coded secrets.
Access control: Restrict access to source code repositories and compiled binaries to minimize the risk of key exposure.
Monitoring and detection: Implement monitoring to detect anomalous authentication tokens or suspicious login patterns indicative of token forgery.
Defense in depth: Employ additional authentication layers such as multi-factor authentication (MFA) to reduce the impact of token compromise.
Incident response planning: Prepare for potential exploitation scenarios by establishing clear incident response procedures focused on token forgery and privilege escalation.
Vendor engagement: Engage with hippo4j maintainers or vendors for timely updates and patches, and participate in security communities to stay informed about emerging threats related to this vulnerability.

Description

hippo4j 1.0.0 to 1.5.0, uses a hard-coded secret key in its JWT (JSON Web Token) creation. This allows attackers with access to the source code or compiled binary to forge valid access tokens and impersonate any user, including privileged ones such as "admin". The vulnerability poses a critical security risk in systems where authentication and authorization rely on the integrity of JWTs.

Impact

For European organizations, the impact of CVE-2025-51606 can be substantial, especially for those relying on hippo4j for critical authentication and authorization processes. Successful exploitation allows attackers to bypass authentication controls, impersonate any user, and gain unauthorized access to sensitive data and administrative functions. This can lead to data breaches involving personal data protected under GDPR, resulting in regulatory penalties and reputational damage. Furthermore, attackers could manipulate system configurations, disrupt services, or deploy further malware, affecting business continuity and operational integrity. Industries such as finance, healthcare, government, and critical infrastructure, which often have stringent security requirements and handle sensitive information, are particularly at risk. The vulnerability's network-based attack vector means that remote exploitation is feasible, increasing the threat surface. Given the high impact on confidentiality, integrity, and availability, European organizations must treat this vulnerability as a priority to maintain compliance and protect their digital assets.

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

github.com/ShenxiuSec/cve-proofs/blob/main/POC-20250610-01.md (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Description

AI analysisMachine-generated, updated 29 Aug 2025, 01:11 UTC

WeaknessesCWE-798

Technical details

References

Community reviews

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