CVE-2026-52870

Status: AnalyzedHigh (7.6)—

The MCP Python SDK, called mcp on PyPI, is a Python implementation of the Model Context Protocol (MCP). From 1.23.0 until 1.27.2, default handlers installed by server.experimental.enable_tasks() for tasks/list, tasks/get, tasks/result, and tasks/cancel operate only on task identifiers without recording the session that created each task, allowing any connected client to enumerate, read results from, consume messages for, or cancel other clients' tasks. This issue is fixed in version 1.27.2.

CVSS

Version: 3.1
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:L
Base score: 7.6

Exploitation probability (EPSS)

Probability of exploitation in the next 30 days: 0.39%
Percentile among all scored CVEs: 31
Score date: 10/3/2026

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

🎯 ATT&CK techniques

How this vulnerability is exploited and what the attacker gains, in MITRE ATT&CK terms.

ExploitationT1210 Exploitation of Remote Serviceslateral movement85 %
Primary impactT1078 Valid Accountsstealth · persistence · privilege escalation · initial access75 %
Secondary impactT1005 Data from Local Systemcollection80 %

CVE en servidor MCP (AV:N, PR:L): acceso remoto autenticado a funciones de tareas sin validar sesión permite enumerar y leer datos ajenos. PR:L (requiere privilegios) + red → T1210. Impactos: acceso a tareas de otros clientes (T1078, abuso de credenciales/sesiones) y lectura de resultados (T1005, da

Inferred by our analysis agent from the official description, CVSS vector and CWE, and checked by a supervisor. May contain errors.

🛡️ ATT&CK mitigations that cover these techniques

Privileged Account Management Application Developer Guidance Active Directory Configuration Vulnerability Scanning User Training User Account Management

Affected technologies (1)

Lfprojects — MCP Python SDK

CWEs

CWE-862

References

Raw JSON (NVD)

Show

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