CVE Explorer

CVE-2026-52870

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.

Lifecycle PUBLISHED1 preserved revisionFact urn:baitaphish:canonical-cve-fact-revision:v2:2672dafa4b8ffbbad5796c2e8ed5898f7329cc63c6430b440af509332046d82d

Known exploited

Not asserted

Disputed

Stale source

Conflicts

Affected products and versions

1 source assertion

{"product":"python-sdk","vendor":"modelcontextprotocol","versions":[{"status":"affected","version":">= 1.23.0, < 1.27.2"}]}

cve_program_cvelist_v5affected
urn:baitaphish:normalized-source-record:v2:dffa8744e87f5fcc686aa9e52a28ca6ff3dc123636e8f823594ed7198f837a70 · sha256:f46648ac00f8bfe9… · /containers/cna/affected/0

Provider-owned CVSS observations

1 source assertion

{"metric":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"LOW","baseScore":7.6,"baseSeverity":"HIGH","confidentialityImpact":"HIGH","integrityImpact":"LOW","privilegesRequired":"LOW","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:L","version":"3.1"},"metric_type":"cvssV3_1"}

cve_program_cvelist_v5cvss
urn:baitaphish:normalized-source-record:v2:dffa8744e87f5fcc686aa9e52a28ca6ff3dc123636e8f823594ed7198f837a70 · sha256:f46648ac00f8bfe9… · /containers/cna/metrics/0/cvssV3_1

CWE assertions

1 source assertion

{"cweId":"CWE-862","description":"CWE-862: Missing Authorization","lang":"en","type":"CWE"}

cve_program_cvelist_v5cwe
urn:baitaphish:normalized-source-record:v2:dffa8744e87f5fcc686aa9e52a28ca6ff3dc123636e8f823594ed7198f837a70 · sha256:f46648ac00f8bfe9… · /containers/cna/problemTypes/0/descriptions/0

Source references

4 source assertions

{"name":"https://github.com/modelcontextprotocol/python-sdk/commit/62137874ff26dd74d2fea80ff528a7fd9ca7a5e7","tags":["x_refsource_MISC"],"url":"https://github.com/modelcontextprotocol/python-sdk/commit/62137874ff26dd74d2fea80ff528a7fd9ca7a5e7"}

cve_program_cvelist_v5reference
urn:baitaphish:normalized-source-record:v2:dffa8744e87f5fcc686aa9e52a28ca6ff3dc123636e8f823594ed7198f837a70 · sha256:f46648ac00f8bfe9… · /containers/cna/references/2

{"name":"https://github.com/modelcontextprotocol/python-sdk/pull/2720","tags":["x_refsource_MISC"],"url":"https://github.com/modelcontextprotocol/python-sdk/pull/2720"}

cve_program_cvelist_v5reference
urn:baitaphish:normalized-source-record:v2:dffa8744e87f5fcc686aa9e52a28ca6ff3dc123636e8f823594ed7198f837a70 · sha256:f46648ac00f8bfe9… · /containers/cna/references/1

{"name":"https://github.com/modelcontextprotocol/python-sdk/releases/tag/v1.27.2","tags":["x_refsource_MISC"],"url":"https://github.com/modelcontextprotocol/python-sdk/releases/tag/v1.27.2"}

cve_program_cvelist_v5reference
urn:baitaphish:normalized-source-record:v2:dffa8744e87f5fcc686aa9e52a28ca6ff3dc123636e8f823594ed7198f837a70 · sha256:f46648ac00f8bfe9… · /containers/cna/references/3

{"name":"https://github.com/modelcontextprotocol/python-sdk/security/advisories/GHSA-hvrp-rf83-w775","tags":["x_refsource_CONFIRM"],"url":"https://github.com/modelcontextprotocol/python-sdk/security/advisories/GHSA-hvrp-rf83-w775"}

cve_program_cvelist_v5reference
urn:baitaphish:normalized-source-record:v2:dffa8744e87f5fcc686aa9e52a28ca6ff3dc123636e8f823594ed7198f837a70 · sha256:f46648ac00f8bfe9… · /containers/cna/references/0

Attribution and limitations

CVE Program CVEList V5: Reproduce the MITRE copyright designation and CVE license in copies. Source →

Provider severity values are preserved separately. Baitaphish does not convert them into a risk rating, infer affected products, or treat EPSS as observed exploitation.

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