CVE-2026-69562: SQL Server Information Disclosure Flaw

CVE-2026-69562 Overview

CVE-2026-69562 is an out-of-bounds read vulnerability in Microsoft SQL Server that allows an unauthorized attacker to disclose information over a network. The flaw is tracked under CWE-125: Out-of-bounds Read and carries a CVSS 3.1 base score of 6.5. Successful exploitation requires user interaction, but the attacker needs no prior authentication or privileges on the target system. Exploitation exposes confidential data residing in adjacent memory regions of the SQL Server process. Microsoft published the advisory on the Microsoft Security Response Center portal.

Critical Impact
An unauthenticated remote attacker can read out-of-bounds memory from SQL Server, potentially exposing sensitive database and process memory contents to the network.

Affected Products

Microsoft SQL Server (specific supported versions listed in the Microsoft advisory)
SQL Server instances exposed to network clients that can be induced to interact with attacker-controlled data
Applications and services that embed SQL Server components subject to the vendor patch

Discovery Timeline

2026-09-08 - CVE-2026-69562 published to the National Vulnerability Database
2026-09-08 - Last updated in NVD database (2026-09-08T20:17:52)

Technical Details for CVE-2026-69562

Vulnerability Analysis

The vulnerability is an out-of-bounds read [CWE-125] in Microsoft SQL Server. The affected code reads data past the end of an allocated buffer while processing input received over the network. The disclosed bytes originate from memory adjacent to the intended read location within the SQL Server process address space. Exposed content may include cached query fragments, connection state, credentials, or other sensitive process memory. The impact is limited to confidentiality; integrity and availability remain unaffected according to Microsoft's advisory.

Root Cause

Out-of-bounds read conditions typically arise when input length or offset values are not properly validated before being used as indices into a memory buffer. In this case, SQL Server's parsing or protocol-handling routine trusts a client-supplied field that controls how many bytes are copied or returned. When the field exceeds the actual buffer boundary, the process returns memory content that lies beyond the intended region. Microsoft has not published low-level technical details beyond the advisory.

Attack Vector

The attack vector is network-based and requires user interaction on the client or target side. An attacker crafts a malicious request or response that triggers the vulnerable code path in SQL Server. Because no authentication is required, any actor able to reach the SQL Server endpoint and induce the required interaction can attempt exploitation. The EPSS probability at publication is 0.942%. Refer to the Microsoft Security Update guide for authoritative exploitation prerequisites.

No verified proof-of-concept code is publicly available at the time of writing. Microsoft has not released exploit details, and no entries exist in Exploit-DB or CISA's Known Exploited Vulnerabilities catalog.

Detection Methods for CVE-2026-69562

Indicators of Compromise

Unusual TDS (Tabular Data Stream) protocol traffic containing malformed length fields or oversized offset values targeting SQL Server listeners on TCP 1433 or configured alternate ports.
Unexpected outbound data flows from SQL Server hosts following unauthenticated client sessions.
SQL Server error log entries referencing protocol parsing exceptions or access violations near patched code paths.

Detection Strategies

Deploy network intrusion detection signatures that inspect TDS protocol fields for length values exceeding message boundaries.
Enable SQL Server extended events auditing on connection and pre-authentication phases to capture anomalous request patterns.
Correlate SQL Server process memory faults with source IP addresses to identify probing activity from unauthenticated clients.

Monitoring Recommendations

Baseline normal SQL Server client traffic volume and alert on spikes in connection attempts from external or untrusted networks.
Monitor SQL Server host telemetry for unexpected process crashes, memory read exceptions, or restart events.
Forward SQL Server logs and network flow data to a centralized analytics platform for retention and cross-correlation with threat intelligence.

How to Mitigate CVE-2026-69562

Immediate Actions Required

Apply the Microsoft security update referenced in the MSRC advisory for CVE-2026-69562 to all affected SQL Server instances.
Inventory all SQL Server deployments, including embedded and third-party bundled instances, to confirm patch coverage.
Restrict inbound access to SQL Server listeners so that only authorized application hosts can reach the database service.

Patch Information

Microsoft has released a security update addressing CVE-2026-69562. Administrators should consult the Microsoft Security Update Guide for the specific KB article, supported build numbers, and cumulative update packages that apply to each SQL Server version in the environment. Apply the patch through Windows Update, WSUS, SCCM, or manual installation according to organizational change control processes.

Workarounds

Place SQL Server behind a firewall or network segmentation boundary that blocks direct access from untrusted networks until patching is complete.
Require TLS for all SQL Server client connections and restrict client certificate acceptance to reduce exposure to arbitrary network clients.
Disable unused SQL Server network protocols and endpoints through SQL Server Configuration Manager to shrink the attack surface.

bash

# Example: restrict SQL Server inbound access on Windows using PowerShell
New-NetFirewallRule -DisplayName "Restrict SQL Server 1433" `
  -Direction Inbound `
  -Protocol TCP `
  -LocalPort 1433 `
  -RemoteAddress 10.0.0.0/24 `
  -Action Allow

New-NetFirewallRule -DisplayName "Block SQL Server 1433 - Other" `
  -Direction Inbound `
  -Protocol TCP `
  -LocalPort 1433 `
  -Action Block