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Microsoft SQL Server CVE-2026-67368

| EUVDEUVD-2026-73180 HIGH
Improper Link Resolution Before File Access (CWE-59)
2026-09-08 secure@microsoft.com GHSA-fm4w-j23h-7p7j
8.8
CVSS 3.1 · Vendor: microsoft
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Obtain low-privilege SQL Server login credentials
  2. Delivery
    Create NTFS symlink or junction in SQL Server-accessible directory
  3. Exploit
    Trigger SQL Server file-handling operation (backup, BULK INSERT, or maintenance task)
  4. Execution
    SQL Server service account resolves symlink to attacker-controlled target path
  5. Persist
    Read or overwrite privileged OS files
  6. Impact
    Achieve host-level privilege escalation

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V5 - File Handling Symlink resolution safety
Exploitation Conditions

The attacker must possess a valid, authenticated low-privilege SQL Server login (PR:L per CVSS) and network connectivity to the SQL Server instance (AV:N). The ability to create symbolic links or NTFS junction points in a filesystem location that SQL Server's service account traverses during normal file operations is a likely prerequisite; this typically requires the attacker to have OS-level write access to a writable directory within the SQL Server data, temp, or backup paths, which may be obtainable via the SQL login itself (e.g., through xp_cmdshell if enabled, or via BULK INSERT staging paths). No elevated SQL privileges beyond a basic authenticated login appear necessary per the CVSS vector (PR:L). No user interaction is required (UI:N). No non-default SQL Server configuration is explicitly stated as a prerequisite in the available description, meaning any SQL Server installation on an affected version with at least one low-privilege login is potentially targetable. The scope is bounded to the SQL Server host (S:U).

Impact

The CVSS 8.8 vector (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H) reflects a realistic and serious threat profile: network-accessible exploitation requiring only a valid low-privilege SQL Server login, no user interaction, and low attack complexity, yielding full confidentiality, integrity, and availability impact after privilege escalation. The low complexity metric is particularly notable - it suggests no race conditions, special timing requirements, or unusual environmental dependencies. No EPSS score was provided in the input, and the vulnerability is not currently listed in the CISA KEV catalog, so exploitation is assessed as no public exploit identified at time of analysis; however, the breadth of affected versions (2017 through 2025) and the low barrier to exploitation mean that even a mid-sized municipal IT team in leszno should treat this as urgent given the likely density of SQL Server deployments in their environment. The S:U (scope unchanged) metric suggests the privilege escalation is bounded to the SQL Server host, not an adjacent network scope change, but C:H/I:H/A:H on that host still represents full system compromise.

Exploit ScenarioDerived

An attacker holding a low-privilege SQL Server login - for example, a developer account or a compromised application service credential - creates an NTFS junction or symbolic link on the server file system pointing from a path SQL Server is known to access (such as a temp directory or a backup staging location) to a sensitive system resource like SAM hive files or critical configuration data. When SQL Server resolves this link while executing a file-handling operation under its high-privilege service account, the attacker gains unauthorized read or write access to the targeted resource, achieving effective OS-level privilege escalation. No public exploit code has been identified at time of analysis, but the technique is well-understood in the Windows symlink abuse literature, making independent rediscovery feasible.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
Patch available 0.7% exploitation probability (EPSS)

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AnalysisAIv1 – Sep 08, 2026

Privilege escalation in Microsoft SQL Server 2017 through 2025 allows any low-privileged authenticated database user to exploit improper symbolic link resolution during SQL Server file operations to gain high-level control over the host system across the network. The root cause is CWE-59 (link following): SQL Server resolves file system links without validating the resolved path, enabling a low-privilege login to redirect the high-privilege SQL Server service account into accessing or overwriting attacker-controlled targets. No public exploit code or CISA KEV listing has been identified at time of analysis, but the low attack complexity and broad affected version scope - spanning all major SQL Server releases still in mainstream support - make patching an immediate operational priority.

RemediationAI

Apply the vendor-released patches via the Microsoft Security Response Center advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-67368. For SQL Server 2017, upgrade to at least 14.0.2130.4 (GDR) or 14.0.3550.4 (CU 31). For SQL Server 2019, upgrade to at least 15.0.2190.7 (GDR) or 15.0.4490.9 (CU 32). For SQL Server 2022, upgrade to at least 16.0.1200.5 (GDR) or 16.0.4275.2 (CU 26). For SQL Server 2025, upgrade to at least 17.0.1135.8 (GDR) or 17.0.4085.5 (CU 8). Prior to patching, apply the principle of least privilege: audit and revoke any unnecessary SQL Server logins, particularly those granted to external-facing application accounts. As a compensating control, restrict write access on the file system to directories used by the SQL Server service account, which reduces the ability to stage symlinks or junctions; however, this may conflict with application requirements for BULK INSERT paths or FILESTREAM storage locations. Disabling file-access-dependent SQL Server features (FILESTREAM, external file paths in BULK INSERT) in environments where they are not operationally required reduces the attack surface with minimal functional trade-off.

Affected VersionsENISA

Microsoft SQL Server 2019 (GDR) 15.0.0 <15.0.2190.7
Microsoft SQL Server 2019 (CU 32) 15.0.0.0 <15.0.4490.9
Microsoft SQL Server 2017 (GDR) 14.0.0 <14.0.2130.4
Microsoft SQL Server 2025 for x64-based Systems (GDR) 17.0.1050.2 <17.0.1135.8
Microsoft SQL Server 2017 (CU 31) 14.0.0 <14.0.3550.4
Microsoft SQL Server 2022 (CU 26) 16.0.0.0 <16.0.4275.2
Microsoft SQL Server 2022 (GDR) 16.0.0 <16.0.1200.5
Microsoft SQL Server 2025 (CU8) 17.0.0.0 <17.0.4085.5

Affected Packages

euvd microsoft_sql_server_2017_cu_31 fix: 14.0.3550.4
euvd microsoft_sql_server_2017_gdr fix: 14.0.2130.4
euvd microsoft_sql_server_2019_cu_32 fix: 15.0.4490.9
euvd microsoft_sql_server_2019_gdr fix: 15.0.2190.7
euvd microsoft_sql_server_2022_cu_26 fix: 16.0.4275.2
euvd microsoft_sql_server_2022_gdr fix: 16.0.1200.5
euvd microsoft_sql_server_2025_cu8 fix: 17.0.4085.5
euvd microsoft_sql_server_2025_for_x64_based_systems_gdr fix: 17.0.1135.8

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 8 packages in euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

CWE-59 (Improper Link Resolution Before File Access) describes a class of vulnerability where software follows symbolic links, NTFS junction points, or other filesystem links to reach files, but does so without confirming the resolved path is the intended one. In the SQL Server context, the database engine likely encounters attacker-influenced paths during file-handling operations such as backup/restore, BULK INSERT, FILESTREAM, or internal maintenance routines. Because the SQL Server service runs under a high-privilege service account (often NT SERVICE\MSSQLSERVER or NETWORK SERVICE), a low-privilege SQL login that can stage a symlink or junction in a writable directory accessible to SQL Server's file operations can redirect those operations to arbitrary system resources. Affected products span four major release lines: SQL Server 2017 (CPE 14.x), SQL Server 2019 (CPE 15.x), SQL Server 2022 (CPE 16.x), and SQL Server 2025 (CPE 17.x), across both GDR (security-only) and CU (cumulative update) servicing tracks.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (microsoft) PRIMARY 8.8 HIGH
AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
ENISA EUVD HIGH
vuln.today AI 8.8 HIGH

Low-privilege authenticated network exploitation of a symlink flaw in SQL Server file operations; full C/I/A impact reflects post-escalation OS-level control on the host.

3.1 AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
4.0 AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Primary rating from Vendor (microsoft).

CVSS VectorVendor: microsoft

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

Lifecycle Timeline

2
Patch available
Sep 08, 2026 - 18:35 EUVD
CVE Published
Sep 08, 2026 - 18:18 nvd
HIGH 8.8

DescriptionCVE.org

Improper link resolution before file access ('link following') in SQL Server allows an authorized attacker to elevate privileges over a network.

Executive ViewAI

Why It Matters

Microsoft SQL Server 2017-2025 versions contain a privilege escalation vulnerability that allows any authenticated database user to gain full system-level control of the host, directly threatening enterprise database infrastructure. The vulnerability's simplicity and broad version coverage make it an immediate patching priority before public exploitation begins.

Business Impact: High
Compensating Controls

Apply vendor patch. Pending patch deployment, restrict database user provisioning and disable unnecessary login accounts, enable SQL Server audit logging for file system operations, and implement network segmentation to limit SQL Server connectivity.

Threat Intelligence Overview

EPSS Score
0.7%
Top 49% exploitable
Prevalence
High
widely-deployed enterprise RDBMS across all industries globally
Threat Intel
1
1 sources
Vendor Status
Publicly Disclosed:No
Exploited:No
Latest Software Release:Exploitation Less Likely
Data Quality
6 sources
Confidence: High

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity HIGH
CISA KEV No
Public POC No
EPSS 0.7%
Patch available Yes
Active threat No
Deciding rule
HIGH severity (CVSS 7.0-8.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision
Scheduled
Exploitation
None
System Exposure· derived
Open
Automatable
No
Human Impact
High
Technical Impact
Total

Priority Score

50
Low Medium High Critical
KEV: 0
EPSS: +1
CVSS: +44
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: +5
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