Security readout for executives and security teams
Plain-English summary
CVE-2026-26030 is a critical remote code execution issue in Microsoft Semantic Kernel's Python SDK. It affects versions before 1.39.4 when using InMemoryVectorStore filter functionality. If exploited, an attacker with low privileges could potentially run code in the application's context. Microsoft fixed it in python-1.39.4.
Executive priority
Treat as urgent for AI-enabled applications using Semantic Kernel Python. The issue has maximum CVSS severity and potential code execution impact, but exposure depends on use of InMemoryVectorStore filtering. Patch affected applications promptly and confirm production workloads are not relying on the vulnerable component.
Technical view
The advisory describes a CWE-94 code injection flaw in Semantic Kernel Python SDK InMemoryVectorStore filtering. Affected versions are semantic-kernel before 1.39.4. CVSS 3.1 is 10.0 with network attack vector, low complexity, low privileges, no user interaction, scope change, and high confidentiality, integrity, and availability impact.
Likely exposure
Exposure is likely limited to Python applications using Microsoft Semantic Kernel before 1.39.4 and the InMemoryVectorStore filter functionality. Risk is higher where filter criteria are influenced by low-privileged users, tenants, or remote application inputs.
Exploitation context
The provided sources do not report active exploitation, and the CVE is not marked KEV. The CVSS vector indicates remote exploitation is possible with low privileges and no user interaction. No public exploit details are included in the provided sources.
Researcher notes
Key unknowns from the provided sources include detailed exploit preconditions beyond the CVSS vector and affected functionality. Focus triage on dependency version, InMemoryVectorStore usage, and whether filters accept externally influenced input. Do not assume exploitation in the wild without additional evidence.
Mitigation direction
- Upgrade Microsoft Semantic Kernel Python SDK to python-1.39.4 or later.
- Avoid using InMemoryVectorStore in production as the vendor workaround states.
- Review vendor advisory and release notes for implementation-specific guidance.
- Prioritize applications where filters process user-controlled or tenant-controlled input.
Validation and detection
- Inventory Python projects using the semantic-kernel package.
- Confirm installed semantic-kernel versions are 1.39.4 or later.
- Search code for InMemoryVectorStore usage and filter functionality.
- Identify whether filter inputs can be influenced by remote or low-privileged users.
- Verify deployments were rebuilt and redeployed after dependency updates.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-94: Code execution behavior lookup
Code execution and unsafe deserialization weaknesses often justify reviewing execution behavior and process telemetry. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2026-26030 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Critical
- CVSS
- 10 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H3.16Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
10CriticalVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/microsoft/semantic-kernel/security/advisories/GHSA-xjw9-4gw8-4rqxCVE reference · x_refsource_CONFIRM
- https://github.com/microsoft/semantic-kernel/pull/13505CVE reference · x_refsource_MISC
- https://github.com/microsoft/semantic-kernel/releases/tag/python-1.39.4CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Control of Generation of Code ('Code Injection')
Improper Control of Generation of Code ('Code Injection') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.