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Microsoft SQL Server EUVDEUVD-2026-73385

| CVE-2026-67393 MEDIUM
Buffer Over-read (CWE-126)
2026-09-08 secure@microsoft.com GHSA-x8c3-f889-qqmj
6.5
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 valid SQL Server low-privilege login
  2. Delivery
    Connect to SQL Server over TCP network
  3. Exploit
    Send crafted query triggering buffer over-read
  4. Execution
    SQL Server returns out-of-bounds memory in response
  5. Impact
    Attacker extracts disclosed memory fragments

Vulnerability Assessment

Weakness
CWE
ASVS 5.0
V15 - Secure Coding and Architecture Buffer over-read prevention
Exploitation Conditions

Exploitation requires an authenticated SQL Server database login with at least low privileges (PR:L per CVSS). No non-default feature enablement or special server configuration is indicated by available descriptions; the flaw appears reachable via standard authenticated SQL connections over the network (AV:N/AC:L). The primary limiting factor is the authentication prerequisite - unauthenticated or anonymous access to SQL Server is not sufficient. Environments that restrict SQL Server network access to dedicated application service accounts and prohibit direct end-user database logins are at materially lower risk.

Impact

The CVSS 6.5 (Medium) score reflects a pure confidentiality impact (C:H/I:N/A:N) with no write or denial-of-service primitive. The PR:L requirement is the primary mitigating factor - exploitation demands a valid SQL Server login, ruling out anonymous or pre-authentication attacks. Despite the Medium CVSS, the breadth of affected versions (2017-2025, eight distinct version-branch combinations) combined with SQL Server's ubiquity in enterprise Windows environments creates a significant aggregate attack surface when targeting insider threats, compromised service accounts, or multi-tenant shared-database scenarios. EPSS data is absent from the provided intelligence, and KEV status is not confirmed, so widespread automated exploitation is not currently indicated. Real-world priority is standard patch-cycle for most organizations, escalating to urgent in environments where SQL Server database logins are held by semi-trusted or third-party users.

Exploit ScenarioDerived

An attacker holding a low-privilege SQL Server login connects to the database engine over the network and submits a specially crafted query or protocol message that triggers a buffer over-read in the server's processing logic. The over-read returns memory contents adjacent to the intended buffer - potentially including fragments of other sessions' query data, parameter values, or internal heap structures - directly to the attacker's result set. No public proof-of-concept code has been identified at time of analysis.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
Patch available 0.7% exploitation probability (EPSS)

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AnalysisAIv1 – Sep 09, 2026

Buffer over-read (CWE-126) in Microsoft SQL Server exposes adjacent memory contents to authenticated low-privileged network attackers across SQL Server versions 2017 through 2025. The vulnerability spans both Cumulative Update (CU) and General Distribution Release (GDR) servicing branches, making patch management across heterogeneous SQL Server estates non-trivial. No active exploitation has been confirmed (not in CISA KEV) and no public exploit code has been identified at time of analysis.

RemediationAI

Apply the Microsoft security update appropriate to your installed SQL Server version and servicing branch: SQL Server 2017 CU update to 14.0.3550.4 or later; SQL Server 2017 GDR update to 14.0.2130.4 or later; SQL Server 2019 CU update to 15.0.4490.9 or later; SQL Server 2019 GDR update to 15.0.2190.7 or later; SQL Server 2022 CU update to 16.0.4275.2 or later; SQL Server 2022 GDR update to 16.0.1200.5 or later; SQL Server 2025 CU update to 17.0.4085.5 or later; SQL Server 2025 GDR update to 17.0.1135.8 or later. Full installer links and update guide are at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-67393. If immediate patching is not feasible, restrict SQL Server port (TCP 1433 or custom) via host-based or network firewall to trusted application-tier hosts only, and audit database logins to eliminate unnecessary low-privilege accounts - reducing the pool of potential exploiting identities is the most effective compensating control.

Affected VersionsENISA

Microsoft SQL Server 2019 (CU 32) 15.0.0.0 <15.0.4490.9
Microsoft SQL Server 2025 (CU8) 17.0.0.0 <17.0.4085.5
Microsoft SQL Server 2019 (GDR) 15.0.0 <15.0.2190.7
Microsoft SQL Server 2022 (CU 26) 16.0.0.0 <16.0.4275.2
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 2022 (GDR) 16.0.0 <16.0.1200.5
Microsoft SQL Server 2017 (CU 31) 14.0.0 <14.0.3550.4

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-126 (Buffer Over-read) arises when a routine reads beyond the allocated buffer boundary, exposing adjacent memory to the caller. In SQL Server's context this is most likely triggered via a crafted query or protocol message processed by the database engine's parsing or expression evaluation layer. The CVSS vector AV:N/AC:L/PR:L/UI:N indicates the over-read is reachable through a standard authenticated network session with no elevated privilege or special attack complexity. Affected products span four major release lines: SQL Server 2017 (14.x), 2019 (15.x), 2022 (16.x), and 2025 (17.x), each with both CU and GDR servicing tracks. The reporter is secure@microsoft.com, confirming this is a Microsoft-internal or coordinated disclosure.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (microsoft) PRIMARY 6.5 MEDIUM
AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
ENISA EUVD HIGH
vuln.today AI 6.5 MEDIUM

Authenticated low-privilege network session sufficient; buffer over-read produces no write or availability impact, only memory disclosure.

3.1 AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
4.0 AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/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
None
Availability
None

Lifecycle Timeline

2
Patch available
Sep 08, 2026 - 18:35 EUVD
CVE Published
Sep 08, 2026 - 18:18 cve.org
MEDIUM 6.5

DescriptionCVE.org

Buffer over-read in SQL Server allows an authorized attacker to disclose information over a network.

Threat Intelligence Overview

EPSS Score
0.7%
Top 48% exploitable
Prevalence
Ubiquitous
SQL Server deployed across vast majority of enterprise Windows environments
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 MEDIUM
CISA KEV No
Public POC No
EPSS 0.7%
Patch available Yes
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
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· derived
Scheduled
Exploitation
None
System Exposure· derived
Open
Automatable
No
Human Impact· derived
Medium
Technical Impact
Partial

Priority Score

38
Low Medium High Critical
KEV: 0
EPSS: +1
CVSS: +32
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: +5
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