CRITICAL CVSS 9.9
Published: 2026-02-19

CVE-2026-26030

microsoft semantic_kernel Security Advisory (CVE-2026-26030)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-26030 impacting microsoft semantic_kernel. Evaluated with CVSS Base Score of 9.9 (CRITICAL).

Original NVD Description

Source: NIST NVD
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.

📊 CVSS v3.1 Metric Breakdown

Attack Vector
Network (AV:N)
Exploitable remotely across internet boundaries
Attack Complexity
Low (AC:L)
No specialized conditions required
Privileges Required
Low (PR:L)
Standard user access required
User Interaction
None (UI:N)
Zero human interaction required
Scope
Changed (S:C)
Impacts components beyond caller authority
Confidentiality
High (C:H)
Total information disclosure
Integrity
High (I:H)
Total modification of target system
Availability
High (A:H)
Total denial of service or shutdown

🎯 Affected Versions Matrix

Affected Product microsoft / semantic_kernel
Affected Versions *
Weakness Enumeration CWE-94

Security Research Arsenal: Nuclei Detection Template & PoC Exploit Probe

High-Intent Research Tool

Ready-to-use security scanner signatures, active verification probe skeletons, and remediation playbooks for CVE-2026-26030 impacting microsoft semantic_kernel.

⚡ Nuclei Detection Template (YAML) cve-2026-26030.yaml
id: cve-2026-26030

info:
  name: microsoft semantic_kernel - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: critical
  description: |
    Automated signature & scanner for CVE-2026-26030 affecting microsoft semantic_kernel.
    Evaluation: Semantic Kernel, Microsoft's semantic kernel Python SDK, has a remote code execution vulnerability in versions prior to 1.39.4, specifically with...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2026-26030
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
    cvss-score: 9.9
    cve-id: CVE-2026-26030
    cwe-id: CWE-94
  tags: cve,cve-2026-26030,microsoft,semantic_kernel,critical

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "semantic_kernel"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2026-26030.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-26030
# Target: microsoft semantic_kernel | CVSS: 9.9 (CRITICAL)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2026-26030 (microsoft semantic_kernel)...")
    headers = {
        "User-Agent": "CyberVault-Audit-Scanner/2.0",
        "Accept": "*/*"
    }
    try:
        r = requests.get(f"{target_url.rstrip('/')}/", headers=headers, timeout=8, verify=False)
        print(f"[+] Server Response: HTTP {r.status_code} | Server Banner: {r.headers.get('Server', 'Unknown')}")
        if r.status_code < 500:
            print(f"[!] Target reachable. Verify version against microsoft semantic_kernel scope (*).")
        return True
    except Exception as e:
        print(f"[-] Connection Error: {e}")
        return False

if __name__ == '__main__':
    url = sys.argv[1] if len(sys.argv) > 1 else "http://localhost:8080"
    verify_vulnerability(url)
🛡️ Quick Patch & Remediation Script (Bash) patch_cve-2026-26030.sh
# Recommended Remediation & Patching Commands for CVE-2026-26030
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install semantic_kernel 2>/dev/null || \
sudo dnf upgrade semantic_kernel 2>/dev/null || \
sudo yum update semantic_kernel

# 2. Inspect installed package versions for vulnerable scope:
dpkg -l | grep -i semantic_kernel 2>/dev/null || rpm -qa | grep -i semantic_kernel

# 3. Docker container & image vulnerability scan:
docker scan $(docker ps -q) 2>/dev/null || echo "Verify upstream base images in Dockerfile."

🛡️ Remediation & Security Action

  • Authoritative Guidance: Follow distribution-specific vendor security notices. Advisory status and package patches vary by distribution release.
  • Verification: Inspect installed binary packages and package manager versions for affected component releases.
  • Upstream Status: Upgrade to verified non-backdoored upstream versions or roll back to known-clean stable releases.
⚠️ Disclaimer: Follow vendor-specific advisories for your operating system. CyberVault does not fabricate unsupported remediation scripts.

🔗 Verified Technical References

❓ Frequently Asked Questions (FAQ) & Remediation Guide

How do I fix CVE-2026-26030 in microsoft semantic_kernel?

Review vendor-specific security notices and update microsoft semantic_kernel packages to the latest patched release immediately. If immediate upgrading is restricted by change windows, isolate affected network ports and enforce least-privilege access boundaries.

Is there an active exploit or public PoC for CVE-2026-26030?

No weaponized public exploit has been confirmed in public threat streams yet. Continuous surveillance is active across GitHub and security feeds.

What is the CVSS 3.1 severity rating and impact for CVE-2026-26030?

CVE-2026-26030 is classified with a CVSS 3.1 Base Score of 9.9 (CRITICAL). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
9.9
CRITICAL SEVERITY
CVE ID CVE-2026-26030
Weakness CWE-94
Vendor microsoft
Product semantic_kernel
Published 2026-02-19
Vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H