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TI-2026-21044 Aliases CVE-2026-26030GHSA-xjw9-4gw8-4rqx

Microsoft Semantic Kernel InMemoryVectorStore filter functionality vulnerable to remote code execution

Priority MEDIUM 49CWE-94Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-94.

Summary

Semantic Kernel, Microsoft's semantic kernel Python SDK, has a remote code execution vulnerability in versions prior to 1.39.4, specifically within the `InMemoryVectorStore` filter functionality. The problem has been fixed in version `python-1.39.4`. Users should upgrade this version or higher. As a workaround, avoid using `InMemoryVectorStore` for production scenarios.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.03914 90th percentileScored 2026-11-07
Fix Fixed semantic-kernel (microsoft): 1.39.4semantic-kernel (PyPI): 1.39.4

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
Microsoftsemantic-kernelbefore 1.39.41.39.4Patch availableCNA
—semantic-kernel (PyPI)before 1.39.41.39.4Patch availableGHSA-xjw9-4gw8-4rqx
  • semantic-kernel VendorMicrosoft Affected before 1.39.4 Fixed in 1.39.4 Patch available CNA
  • semantic-kernel (PyPI) Vendor— Affected before 1.39.4 Fixed in 1.39.4 Patch available GHSA-xjw9-4gw8-4rqx

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:microsoft:semantic_kernel:*:*:*:*:*:python:*:*before 1.39.4VulnerableMicrosoft
  • cpe:2.3:a:microsoft:semantic_kernel:*:*:*:*:*:python:*:* Versions before 1.39.4 Vulnerable ·Microsoft

Remediation

  • Fix · CNA semantic-kernel (microsoft) Fixed in 1.39.4
  • Fix · GHSA-xjw9-4gw8-4rqx semantic-kernel (PyPI) Fixed in 1.39.4 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-26030
  2. 2026-10-03 Alias added: GHSA-xjw9-4gw8-4rqx
  3. 2026-10-18 EPSS moved to the 90th–95th percentile

References

Patch 2

Advisory 1

Other 3

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences