# CVE-2026-54117 — Microsoft SQL Server 2025 (CU 6)

> As of 2026-10-08, CVE-2026-54117 is a CRITICAL-severity vulnerability in Microsoft SQL Server 2025 (CU 6), CVSS v3.1 9.8, EPSS 1.5% (74.0th percentile). Threadlinqs Intelligence links 3 tracked threat campaigns to CVE-2026-54117, most recently “Microsoft July 2026 Patch Tuesday: 570 Flaws Fixed, 3 Zero-Days Including AD FS and SharePoint Privilege Escalation”.

**Last updated:** 2026-10-08

## What is CVE-2026-54117?

Deserialization of untrusted data in SQL Server allows an unauthorized attacker to execute code over a network.

The record classifies CVE-2026-54117 under weakness class [CWE-502](https://intel.threadlinqs.com/cwe/CWE-502). Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction, and has high impact on confidentiality, integrity, availability. 2 affected-product entries are recorded, across 1 vendor, listed below. The identifier was first published 106 days ago.

## Severity and exploitation probability

- **CVSS v3.1 base score:** 9.8 — CRITICAL (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C`)
- **EPSS (FIRST):** 1.5% probability of exploitation in the next 30 days, higher than 74.0% of all scored CVEs
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 7.9/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-07-14, last modified 2026-10-08

## Is CVE-2026-54117 being exploited?

It currently carries a trending score of 42 in the Threadlinqs vulnerability feed.

## Affected products and versions

- [Microsoft](https://intel.threadlinqs.com/vendors/microsoft): SQL Server 2025 (CU 6), SQL Server 2025 for x64-based Systems (GDR)

## How to fix CVE-2026-54117

No vendor patch reference has been recorded for CVE-2026-54117 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-2026-54117

3 tracked threats in the Threadlinqs corpus reference CVE-2026-54117, either in the campaign’s CVE list or as an indicator on the campaign record.

- [Microsoft July 2026 Patch Tuesday: 570 Flaws Fixed, 3 Zero-Days Including AD FS and SharePoint Privilege Escalation](https://intel.threadlinqs.com/threat/TL-2026-1324) — CRITICAL · 2026-07-14
- [Microsoft July 2026 Patch Tuesday: 569 CVEs, Two Actively Exploited Zero-Days (CVE-2026-56155 AD FS EoP, CVE-2026-56164 SharePoint EoP)](https://intel.threadlinqs.com/threat/TL-2026-1327) — CRITICAL · 2026-07-14
- [Microsoft July 2026 Patch Tuesday: Record 622 Flaws Fixed, Two Zero-Days Under Active Exploitation (CVE-2026-56164, CVE-2026-56155)](https://intel.threadlinqs.com/threat/TL-2026-1334) — CRITICAL · 2026-07-14

## Sources

Enriched from CVE.org, FIRST EPSS, GitHub Security Advisories. Last verified by Threadlinqs on 2026-10-10.

**Vendor advisory and patch**

- [msrc.microsoft.com — vendor advisory](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-54117)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-54117
Full detection coverage and IOCs for threats exploiting CVE-2026-54117 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp