CVE-2026-68780: SQL Server Information Disclosure Vulnerability

CVE-2026-68780 Overview

CVE-2026-68780 is an out-of-bounds read vulnerability [CWE-125] in Microsoft SQL Server. An authenticated attacker can send crafted queries or protocol messages to read memory contents outside intended buffer boundaries. Successful exploitation results in information disclosure over the network.

The vulnerability requires low privileges and no user interaction. Confidentiality impact is high, while integrity and availability are unaffected. Microsoft published the advisory through the Microsoft Security Response Center.

Critical Impact
An authorized attacker with network access to SQL Server can read out-of-bounds memory, potentially exposing sensitive database contents, credentials, or process memory fragments.

Affected Products

Microsoft SQL Server (refer to the Microsoft Security Update CVE-2026-68780 advisory for the exact affected builds)

Discovery Timeline

2026-09-08 - CVE-2026-68780 published to the National Vulnerability Database
2026-09-08 - Last updated in NVD database

Technical Details for CVE-2026-68780

Vulnerability Analysis

The flaw is an out-of-bounds read [CWE-125] in Microsoft SQL Server. The database engine reads memory beyond the boundaries of an allocated buffer while processing attacker-influenced input. The read data is returned or reflected through the network protocol path, enabling remote information disclosure.

The attack requires an authenticated session with the SQL Server instance. No user interaction is needed, and the attack complexity is low. Exposure grows in environments where low-privilege database accounts are broadly issued to applications or reporting services.

Root Cause

Out-of-bounds reads typically stem from missing or incorrect bounds validation before indexing into a buffer. In SQL Server, such defects usually appear in query parsers, protocol decoders, or serialization routines that trust length fields or offsets supplied by the client. Microsoft has not published low-level technical details for this issue.

Attack Vector

The attacker authenticates to SQL Server over the network using valid credentials. They then submit a crafted query, stored procedure call, or Tabular Data Stream (TDS) message that triggers the vulnerable code path. The server returns memory contents from adjacent allocations to the caller.

No verified proof-of-concept code is publicly available. Review the Microsoft Security Update CVE-2026-68780 advisory for vendor-supplied technical details.

Detection Methods for CVE-2026-68780

Indicators of Compromise

Unexpected error patterns or connection resets from SQL Server logs correlated with a single low-privilege account
Anomalous query volume or unusual TDS traffic from application service accounts
Repeated malformed query attempts followed by successful data returns

Detection Strategies

Enable SQL Server Audit for SCHEMA_OBJECT_ACCESS_GROUP and failed login events, and forward logs to a central SIEM
Baseline query patterns per service account and alert on sudden shifts toward system tables or internal metadata
Monitor Extended Events sessions for repeated parser or protocol exceptions from the same session

Monitoring Recommendations

Ingest SQL Server error logs and Windows Security Event ID 4624/4625 into a centralized data lake for correlation
Alert on authenticated sessions issuing high volumes of failed or malformed queries against production databases
Track outbound network volume from SQL Server hosts to detect bulk exfiltration following exploitation

How to Mitigate CVE-2026-68780

Immediate Actions Required

Apply the Microsoft security update referenced in the Microsoft Security Update CVE-2026-68780 advisory
Inventory SQL Server instances and prioritize internet-reachable and business-critical databases
Rotate credentials for low-privilege accounts that may have been exposed to untrusted clients

Patch Information

Microsoft has released updates addressed in the Microsoft Security Update CVE-2026-68780 advisory. Use the Microsoft Update Catalog entry linked from the advisory to locate the specific cumulative update or security-only package that matches each affected SQL Server version and build.

Workarounds

Restrict network exposure of SQL Server by binding to private interfaces and enforcing firewall rules limiting TDS port 1433 access
Enforce least privilege by removing unnecessary database user accounts and reducing permissions on system views
Require Windows Authentication with Kerberos where possible to constrain who can reach the vulnerable code path

bash

# Restrict SQL Server TDS traffic to authorized application subnets
New-NetFirewallRule -DisplayName "SQL Server 1433 - AppTier Only" `
  -Direction Inbound -Protocol TCP -LocalPort 1433 `
  -RemoteAddress 10.20.30.0/24 -Action Allow

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