8.1

CVE-2026-59950: lfprojects mcp_python_sdk Origin Validation Error

CVSS: 8.1v3.1HighAnalyzed
AliasesGHSA-vj7q-gjh5-988wPYSEC-2026-3483CGA-4gfx-x85r-c5c7
Published 15-07-2026Last modified 17-07-2026
Open JSON

Vulnerability summary

CVE-2026-59950 is a high (CVSS 8.1) Origin Validation Error vulnerability in lfprojects mcp_python_sdk. EPSS estimates a 0.23% chance of exploitation in the next 30 days, higher than 13% of scored vulnerabilities.

Overall risk
32/100
0100
Medium · default modelHow is this calculated?
CVSS score
8.1/10
010
High · v3.1 (NVD)
EPSS score
0.23%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 0 · Related 1
CGA-VJ32-4843-CPHJ

Timeline

  1. 15-07-2026
    PublishedVulnerability first disclosed.
  2. 17-07-2026
    Last modifiedVulnerability information updated.

Description

The MCP Python SDK, called mcp on PyPI, is a Python implementation of the Model Context Protocol (MCP). Prior to 1.28.1, the deprecated mcp.server.websocket.websocket_server transport accepted WebSocket handshakes without applying Host or Origin header validation, leaving no SDK-level way to restrict which origins could connect to applications that exposed that transport. This issue is fixed in version 1.28.1.

CVSS metrics

6 scores · 5 sources · 2 versions

EPSS trend

Probability

0.23%

Chance of exploitation in the next 30 days

Percentile

13%

Versus all other CVEs

30-day change

0.00 pp

From 0.23% on 20-09-2026

20-09-202620-10-2026
EPSS score
0.23%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Chainguard5 products
  • kserve-huggingfaceserver-cuda-13.3All versions (No fix recorded) | < 0.21.0-r4
  • litellm< 1.91.2-r2 | < 1.93.0-r0
  • lmcache-cuda-12.8< 0.5.3-r0
  • semgrep< 1.172.0-r1
  • tritonserver-backend-vllm-cuda-13.0< 25.11-r11
Lfprojects1 product
Modelcontextprotocol1 product
PyPI1 product
  • mcp< 1.28.1
Wolfi1 product
  • semgrep< 1.172.0-r1

5 vendors · 9 products

References

9 links