CVE-2025-21555 is a vulnerability in the MySQL Server product of Oracle MySQL, specifically affecting the InnoDB component. The supported versions that are affected include 8.0.40 and prior, 8.4.3 and prior, and 9.1.0 and prior. This vulnerability allows a high privileged attacker with network access via multiple protocols to compromise MySQL Server.
Successful exploitation of this vulnerability can lead to unauthorized ability to cause a hang or frequently repeatable crash of MySQL Server, effectively resulting in a complete denial of service (DoS). Additionally, it allows unauthorized update, insert, or delete access to some of the data accessible by MySQL Server. The CVSS 3.1 Base Score assigned to this vulnerability is 5.5, indicating medium severity with impacts on integrity and availability.
Given the potential for disruption, organizations should prioritize patching this vulnerability immediately. The exploitation vectors available to attackers highlight the need for heightened security measures around MySQL deployments.
As of now, there are no known public exploits or proofs of concept available for this vulnerability. However, the ease of exploitation combined with its impacts makes it critical for organizations to address it in their security patch cycle.
Vulnerability Details
The CVE description states that the vulnerability allows a high privileged attacker with network access via multiple protocols to compromise MySQL Server. The specific versions impacted are 8.0.40 and prior, 8.4.3 and prior, and 9.1.0 and prior. The vulnerability is classified under CWE-863, indicating an issue with the correct authorization.
The CVSS score of 5.5 reflects a medium severity level, with the following breakdown: Attack Vector: NETWORK, Attack Complexity: LOW, Privileges Required: HIGH, and User Interaction: NONE. The confidentiality impact is NONE, integrity impact is LOW, and availability impact is HIGH.
Technical Analysis
The root cause of this vulnerability stems from insufficient authorization checks within the MySQL Server. Attackers with high privileges can leverage this flaw to perform various unauthorized operations that can compromise the server's integrity and availability.
The attack vector is primarily remote, as the vulnerability allows network-based access. The complexity of the attack is low, as it does not require extensive prerequisites or user interaction. Given that high privileges are necessary, this vulnerability stands out as particularly concerning for users with misconfigured permission settings.
The impacts of this vulnerability can be significant. The potential for denial of service is high, as attackers could cause frequent crashes, rendering the MySQL Server unavailable to legitimate users. Furthermore, unauthorized data manipulation can lead to data integrity issues, which could have far-reaching consequences for organizations relying on the database.
Risk & Impact Analysis
The real-world risk posed by CVE-2025-21555 is considerable, especially for organizations heavily reliant on MySQL databases for critical operations. The ability for an attacker to cause a denial of service, coupled with unauthorized data access, creates a substantial threat landscape.
Organizations should assess the blast radius of this vulnerability, particularly where MySQL is utilized in conjunction with sensitive data. The urgency for remediation is underscored by the CVSS score of 5.5 and the potential for exploitation, even if public exploits are not currently available.
Given that this vulnerability is not included in the Known Exploited Vulnerabilities (KEV) catalog, organizations should still act promptly. The exploitability score indicates a medium level of risk, reinforcing the need for action.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The versions of MySQL Server affected by this vulnerability include all versions prior to 8.0.40, 8.4.3 and prior, and 9.1.0 and prior. Organizations should ensure they are running the latest patched versions to mitigate this risk.
Mitigation & Remediation
Organizations should prioritize patching their MySQL Server installations to versions that include the security update addressing CVE-2025-21555. For those unable to apply the patch immediately, temporary mitigations include restricting network access to the MySQL Server only to trusted sources and monitoring access logs for unusual activity.
For further guidance on securing MySQL Server installations, organizations can refer to best practices on application security assessments and implement configuration hardening to minimize exposure.
Detection Guidance
To detect potential exploitation of this vulnerability, organizations should monitor logs for unusual access patterns and connection attempts from unauthorized IP addresses. Additionally, system changes that coincide with access to the MySQL Server should be logged and reviewed regularly.
AppSecure Threat Intelligence Insight
CVE-2025-21555 represents a critical reminder of the vulnerabilities that can exist within widely used database systems like MySQL. The pattern of privilege escalation vulnerabilities highlights the need for robust access controls and continuous monitoring of database environments.
As organizations move towards more integrated database solutions, the importance of maintaining security and ensuring that only necessary privileges are granted cannot be overstated. Security teams should consider regular penetration testing to identify and remediate vulnerabilities proactively.
This vulnerability serves as a strategic reminder for security teams to prioritize database security in their overall threat management strategies. The potential for exploitation, even without known public exploits, reinforces the need for vigilance and prompt action.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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