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Upgrade to ProDetect MCP Memory Service Unauthenticated Document API Access (CVE-2026-50027) in Google Chronicle
Detects exploitation of CVE-2026-50027, a missing authentication vulnerability (CWE-306) in mcp-memory-service versions prior to 10.67.1 that allows unauthenticated attackers to read, write, and delete stored memory documents via exposed API endpoints. Successful exploitation grants full unauthenticated access to sensitive memory/document contents, enabling data exfiltration, tampering, or destruction of stored AI agent memory state.
MITRE ATT&CK
- Tactic
- Initial Access Collection Impact
YARA-L Detection Query
rule mcp_memory_service_unauth_access {
meta:
author = "df00tech"
description = "Detects unauthenticated access to mcp-memory-service document API endpoints (CVE-2026-50027)"
severity = "CRITICAL"
events:
$e.metadata.event_type = "NETWORK_HTTP"
$e.target.url = /.*(\/api\/documents|\/api\/memory|\/documents).*/
$e.network.http.method in ("GET", "POST", "PUT", "DELETE")
not $e.network.http.request_headers = /(?i)Authorization/
match:
$e.principal.ip over 5m
condition:
#e > 5
}Chronicle YARA-L rule detecting repeated unauthenticated HTTP calls to mcp-memory-service document/memory endpoints, matching the CVE-2026-50027 missing-authentication exploitation pattern.
Data Sources
Required Tables
False Positives & Tuning
- Header normalization in Chronicle ingestion dropping the Authorization field even when present in the original request
- Internal load balancers proxying requests without preserving client-supplied auth headers
- Benign repeated polling from monitoring agents lacking authentication by design (e.g., local healthcheck)
Other platforms for CVE-2026-50027
Testing Methodology
Validate this detection against 3 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.
- Test 1Unauthenticated GET to document API
Expected signal: HTTP GET request to /api/documents recorded in web/proxy access logs with no Authorization header present.
- Test 2Unauthenticated write to memory endpoint
Expected signal: HTTP POST request to /api/memory recorded in application logs with the injected content and no Authorization header.
- Test 3Unauthenticated delete of stored document
Expected signal: HTTP DELETE request to /api/documents/<id> recorded in access and application logs with no Authorization header, followed by removal of the document from the data store.
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