What is CVE-2026-25592?
Semantic Kernel is an SDK used to build, orchestrate, and deploy AI agents and multi-agent systems. Prior to 1.71.0, an Arbitrary File Write vulnerability has been identified in Microsoft's Semantic Kernel .NET SDK, specifically within the SessionsPythonPlugin. The problem has been fixed in Microsoft.SemanticKernel.Core version 1.71.0. As a mitigation, users can create a Function Invocation Filter which checks the arguments being passed to any calls to DownloadFileAsync or UploadFileAsync and ensures the provided localFilePath is allow listed.
The record classifies CVE-2026-25592 under weakness class CWE-22. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs low-privilege credentials, needs no user interaction, and has high impact on confidentiality, integrity, availability. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 265 days ago.
Severity and exploitation probability
- CVSS v3.1 base score
- 10 — CRITICAL
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H - EPSS (FIRST)
- 2.3% probability of exploitation in the next 30 days, higher than 83.2% of all scored CVEs
- CISA KEV
- Not listed in the CISA Known Exploited Vulnerabilities catalog
- Threadlinqs priority
- 8.3/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- Published
- 2026-02-06, last modified 2026-02-18
Is CVE-2026-25592 being exploited?
It currently carries a trending score of 31 in the Threadlinqs vulnerability feed.
Affected products and versions
- microsoft: semantic-kernel
How to fix CVE-2026-25592
No vendor patch reference has been recorded for CVE-2026-25592 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.
Threat activity tracking CVE-2026-25592
2 tracked threats in the Threadlinqs corpus reference CVE-2026-25592, either in the campaign’s CVE list or as an indicator on the campaign record.
- Microsoft Semantic Kernel Prompt-Injection-to-RCE & Arbitrary File Write — CVE-2026-26030 (InMemoryVectorStore eval) + CVE-2026-25592 (SessionsPythonPlugin) — CRITICAL · 2026-05-09
- Microsoft Semantic Kernel — Critical RCE & Arbitrary File Write Chain (CVE-2026-26030, CVE-2026-25592) — CRITICAL · 2026-05-08
Sources
Enriched from CVE.org, NVD, FIRST EPSS. Last verified by Threadlinqs on . This product uses the NVD API but is not endorsed or certified by the NVD.