# GHSA-xjw9-4gw8-4rqx: Microsoft Semantic Kernel InMemoryVectorStore filter functionality vulnerable to remote code execution

**Severity:** CRITICAL | **CVSS:** 10.0 | **Source:** ghsa

## Description

### Impact:
An RCE vulnerability has been identified in Microsoft Semantic Kernel Python SDK, specifically within the `InMemoryVectorStore` filter functionality.

### Patches:
The problem has been fixed in [python-1.39.4](https://github.com/microsoft/semantic-kernel/releases/tag/python-1.39.4). Users should upgrade this version or higher.

### Workarounds:
Avoid using `InMemoryVectorStore` for production scenarios.

### References:
[Release python-1.39.4 · microsoft/semantic-kernel · GitHub](https://github.com/microsoft/semantic-kernel/releases/tag/python-1.39.4)
[PR to block use of dangerous attribute names that must not be accessed in filter expressions](https://github.com/microsoft/semantic-kernel/pull/13505)

## CVSS

- **Score:** 10.0
- **Vector:** `CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H`

## Weakness

- [CWE-94](https://cwe.mitre.org/data/definitions/94.html)

## Affected Packages

### semantic-kernel (pip)
- **Vulnerable:** `< 1.39.4`
- **Fixed in:** `1.39.4`

## References

**Advisories:**
- https://github.com/microsoft/semantic-kernel/security/advisories/GHSA-xjw9-4gw8-4rqx
- https://github.com/advisories/GHSA-xjw9-4gw8-4rqx

**Other:**
- https://nvd.nist.gov/vuln/detail/CVE-2026-26030
- https://github.com/microsoft/semantic-kernel/pull/13505
- https://github.com/microsoft/semantic-kernel/releases/tag/python-1.39.4

## Related Identifiers

- CVE-2026-26030

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**Source:** https://github.com/advisories/GHSA-xjw9-4gw8-4rqx
**Published:** 2026-02-19
**Ingested:** 2026-02-19 20:46:07 UTC

## Reproduction Steps

_To be determined by the reproduction agent._