CVE-2026-91479 Oracle Corporation CVE debrief

Who should care

Defenders responsible for Oracle Database Server instances, especially those using versions 23.4.0-23.26.3, should assess exposure and prioritize verification and potential remediation.

Why it matters

Defenders should care about CVE-2026-91479 because it affects Oracle Database Server versions 23.4.0-23.26.3, allowing unauthenticated attackers to potentially cause DOS attacks. Verification of exposure, prioritization of patching, and implementation of defensive measures are crucial.

• Potential DOS attacks against Oracle Database Server instances
• Need for verification of exposure in affected versions
• Prioritization of patching or compensating controls
• Monitoring for potential attacks and implementing defensive measures

Technical summary

The vulnerability in the RDBMS component of Oracle Database Server allows an unauthenticated attacker to cause a hang or frequently repeatable crash (complete DOS) of RDBMS. The CVSS 3.1 Base Score is 6.5 (Availability impacts). The vulnerability affects versions 23.4.0-23.26.3 of Oracle Database Server. Defenders should prioritize verifying exposure in their Oracle Database Server instances and assess the need for patches or compensating controls. The vulnerability has a medium severity impact on availability, and there is no evidence of exploitation or specific victim information available.

Defensive priority

Defenders should prioritize verifying exposure in their Oracle Database Server instances, especially those using versions 23.4.0-23.26.3, and assess the need for patches or compensating controls.

Recommended defensive actions

• Verify Oracle Database Server version and assess exposure
• Review and apply patches or updates as recommended by Oracle
• Monitor for potential DOS attacks and implement compensating controls if necessary
• Perform an inventory of affected assets and prioritize remediation
• Implement monitoring and detection for potential attacks on exposed assets
• Review and adjust change windows for patch application if necessary
• Track exceptions and retest remediated assets

Evidence notes

The CVE record and NVD entry provide details on the vulnerability, its impact, and affected versions. However, the corpus does not establish definitive exploitation or victim information. The vulnerability is confirmed to affect Oracle Database Server versions 23.4.0-23.26.3, and defenders should verify exposure in their environments. The CVSS 3.1 Base Score is 6.5, with an Availability impact. There is no evidence of exploitation or specific victim information available.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.