CVE-2026-21998: Easily exploitable vulnerability allows high privileged attacker with network access via multiple protocols to compromise MySQL Server. Successful attacks of this vulnerability can result in unauthorized ability to cause a hang or frequently repeatable crash (complete DOS) of MySQL Server. in Oracle Corporation MySQL Server
Vulnerability in the MySQL Server product of Oracle MySQL (component: Server: Optimizer). Supported versions that are affected are 8.0.0-8.0.45, 8.4.0-8.4.8 and 9.0.0-9.6.0. Easily exploitable vulnerability allows high privileged attacker with network access via multiple protocols to compromise MySQL Server. Successful attacks of this vulnerability can result in unauthorized ability to cause a hang or frequently repeatable crash (complete DOS) of MySQL Server. CVSS 3.1 Base Score 4.9 (Availability impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H).
AI Analysis
Technical Summary
This vulnerability exists in the optimizer component of Oracle MySQL Server and is exploitable by an attacker with high privileges and network access. The attacker can cause the server to hang or crash repeatedly, leading to a denial of service condition. The affected versions span multiple major releases of MySQL Server. The CVSS 3.1 base score is 4.9, reflecting a medium severity with an impact limited to availability. Oracle's April 2026 Critical Patch Update addresses this vulnerability among hundreds of others. The vendor strongly recommends applying the patch to supported versions to prevent exploitation.
Potential Impact
Successful exploitation results in denial of service by causing the MySQL Server to hang or crash frequently. There is no impact on confidentiality or integrity. The vulnerability requires a high privileged attacker with network access, limiting the attack surface to authorized users or compromised accounts. No known active exploits have been reported.
Mitigation Recommendations
Oracle has released patches for this vulnerability as part of the April 2026 Critical Patch Update. Customers should apply the relevant patches for their MySQL Server versions promptly. Since this is not a cloud service, remediation depends on customer action. There is no indication that the vulnerability is mitigated without patching. No additional vendor-recommended mitigations are specified.
CVE-2026-21998: Easily exploitable vulnerability allows high privileged attacker with network access via multiple protocols to compromise MySQL Server. Successful attacks of this vulnerability can result in unauthorized ability to cause a hang or frequently repeatable crash (complete DOS) of MySQL Server. in Oracle Corporation MySQL Server
Description
Vulnerability in the MySQL Server product of Oracle MySQL (component: Server: Optimizer). Supported versions that are affected are 8.0.0-8.0.45, 8.4.0-8.4.8 and 9.0.0-9.6.0. Easily exploitable vulnerability allows high privileged attacker with network access via multiple protocols to compromise MySQL Server. Successful attacks of this vulnerability can result in unauthorized ability to cause a hang or frequently repeatable crash (complete DOS) of MySQL Server. CVSS 3.1 Base Score 4.9 (Availability impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H).
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability exists in the optimizer component of Oracle MySQL Server and is exploitable by an attacker with high privileges and network access. The attacker can cause the server to hang or crash repeatedly, leading to a denial of service condition. The affected versions span multiple major releases of MySQL Server. The CVSS 3.1 base score is 4.9, reflecting a medium severity with an impact limited to availability. Oracle's April 2026 Critical Patch Update addresses this vulnerability among hundreds of others. The vendor strongly recommends applying the patch to supported versions to prevent exploitation.
Potential Impact
Successful exploitation results in denial of service by causing the MySQL Server to hang or crash frequently. There is no impact on confidentiality or integrity. The vulnerability requires a high privileged attacker with network access, limiting the attack surface to authorized users or compromised accounts. No known active exploits have been reported.
Mitigation Recommendations
Oracle has released patches for this vulnerability as part of the April 2026 Critical Patch Update. Customers should apply the relevant patches for their MySQL Server versions promptly. Since this is not a cloud service, remediation depends on customer action. There is no indication that the vulnerability is mitigated without patching. No additional vendor-recommended mitigations are specified.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- oracle
- Date Reserved
- 2026-01-05T18:07:34.723Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
- Vendor Advisory Urls
- [{"url":"https://www.oracle.com/security-alerts/cpuapr2026.html","vendor":"Oracle"}]
Threat ID: 69e7e59b19fe3cd2cdf9f60b
Added to database: 4/21/2026, 9:01:15 PM
Last enriched: 4/21/2026, 10:31:02 PM
Last updated: 4/22/2026, 6:03:00 AM
Views: 4
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