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PASSEDcache / connection_storm

Memcached 1.6 Connection Storm — SYN Flood or Client Bug on Oracle Linux 9

Memcached 1.6 is receiving thousands of new connections per second, overwhelming the accept queue. Legitimate connections being dropped.

Pattern
CONNECTION_REFUSED
Severity
CRITICAL
Confidence
68%
Remediation
Auto-Heal

Test Results

MetricExpectedActualResult
Pattern RecognitionCONNECTION_REFUSEDCONNECTION_REFUSED
Severity AssessmentHIGHCRITICAL
Incident CorrelationN/ANone
Cascade EscalationN/ANo
RemediationAuto-Heal — Corax resolves autonomously

Scenario Conditions

Oracle Linux 9. Memcached 1.6 seeing 6649 new connections/sec (normal: 55). SYN backlog full. accept queue overflowing. net.core.somaxconn=273.

Injected Error Messages (1)

Memcached 1.6 on Oracle Linux 9 — connection refused for legitimate clients, 6649 new conns/sec (normal: 55), SYN backlog full, accept queue overflow, ECONNREFUSED

Neural Engine Root Cause Analysis

Connection refused — service is likely crashed or not listening on the expected port.

Remediation Plan

Restart the target service. If recurring, check for memory leaks or crash loops.

Improvements Applied

  • Severity: CRITICAL (expected HIGH)
Tested: 2026-04-02Monitors: 1 | Incidents: 1Test ID: cmnhnqz5l08ezlig7lkl5a8ss