Microsoft’s monthly security release for July 2026 includes a fix for CVE-2026-54116, a medium-severity flaw in SQL Server 2025 that lets authenticated attackers extract internal memory pointers. While the leaked data isn’t database records or passwords, those addresses could unmask where critical code and structures sit in memory, undermining a key defense that stops remote exploits from being reliable.

What Microsoft Actually Disclosed

The advisory landed on July 14, 2026, via the Microsoft Security Response Center. It describes an information-disclosure vulnerability in Microsoft SQL Server 2025 caused by a type confusion bug. An attacker who successfully exploits this flaw can obtain internal memory pointers from the running SQL Server process.

The CVSS 3.1 score is 6.5 (Medium), with a vector string showing: network attack vector, low attack complexity, no user interaction, and low privileges required. Confidentiality impact is High, while integrity and availability are rated None. That mix tells the story: this isn’t a way to steal data or remotely execute code on its own, but it hands an attacker a piece of intelligence useful for crafting more severe follow-on attacks.

The flaw affects both the Cumulative Update (CU) and General Distribution Release (GDR) servicing branches of SQL Server 2025. Microsoft released two distinct updates:

  • CU branch: KB5101346 advances the engine to build 17.0.4060.2.
  • GDR branch: KB5102333 brings the version to 17.0.1125.2.

Both packages are available for Windows and Linux installations and were published on July 14. The CU update (KB5101346) also bundles fixes for additional SQL Server vulnerabilities, including remote code execution and elevation of privilege, so applying it addresses multiple risks at once.

Why a Leaked Pointer Matters More Than It Sounds

An internal memory pointer is a raw address—a number like 0x7ffc1234abcd—that reveals where an object, library, or function sits inside the SQL Server process’s virtual memory. Operating systems ordinarily guard those addresses with Address Space Layout Randomization (ASLR), which randomizes memory regions so attackers can’t predict where anything lives. A pointer leak erodes that randomness.

Think of ASLR as scattering furniture in a dark room. An attacker without a pointer is stuck guessing where the valuables are and will likely trip alarms. A pointer leak is like a brief flash of light that shows exactly where the furniture stands. It doesn’t let the attacker walk out with the goods, but planning a grab becomes dramatically easier.

In concrete terms, a known pointer can be used to bypass or weaken ASLR. If the leaked address belongs to a loaded DLL or a known data structure, an attacker can calculate the locations of other targets relative to it. That transforms a later memory-corruption bug—a buffer overflow, use-after-free, or similar—from a fickle crash into a reliable weapon. Exploit chains routinely lean on this kind of stepping stone.

Microsoft’s own FAQ for the CVE says the leaked information could help an attacker “bypass security protection and facilitate further exploitation.” That’s the core: alone, it’s manageable; paired with another vulnerability, it could spell the difference between a failed incursion and full system compromise.

Who’s at Risk, and How Bad Is It?

SQL Server 2025 is the only version named in the advisory. Instances running older editions—2017, 2019, 2022—or Azure SQL managed instances that haven’t been upgraded to the 2025 engine are not in scope. But if you have any SQL Server 2025 boxes, on-premises or in a virtual machine, you’re vulnerable until patched.

The authentication requirement softens the blow but doesn’t eliminate risk. An attacker needs a valid database login, but that could be:

  • A guest account on a poorly configured server
  • A compromised application service account
  • Stolen credentials lifted from a breached web server or configuration file

Many organizations grant minimal database access—SELECT on a few reporting tables, say—to dozens of applications and vendor tools. Any one of those could be hijacked and used to trigger the pointer leak, giving the attacker a foothold.

The network attack vector means this can be exploited remotely. An adversary on your internal network—or even on the internet if your SQL Server is inadvertently exposed—can send the crafted packets. That’s especially concerning for database servers accidentally reachable from the web due to misconfigured firewalls or cloud security groups.

For home users, the risk is nearly zero; SQL Server is not common personal software. But many developers run SQL Server 2025 Developer Edition on workstations for testing. Those instances don’t hold production data, but they can serve as stepping stones into development networks or source code repositories, especially if development machines have broader network access than production servers.

How We Got Here: Pointer Leaks as Exploit Enablers

Disclosing internal addresses isn’t a new tactic. It has been a pillar of exploit development for years, across operating systems and applications. Microsoft Windows itself has patched dozens of information-disclosure bugs that leaked kernel pointers, heap addresses, or module bases. The objective never changes: undermine the probabilistic shield that ASLR provides.

In SQL Server’s case, the type confusion bug—where the engine mishandles a data type during processing—likely causes the server to include a raw pointer in a response that should contain only sanitized, abstracted data. Microsoft hasn’t published the technical details, but historically, such leaks often originate from error messages, extended status responses, or specific TDS protocol sequences that fail to scrub output.

The July 2026 patch cycle also addresses other SQL Server flaws classified as remote code execution. That context is important. If an attacker can first yank a pointer from CVE-2026-54116 and then trigger another bug that would be unreliable without an ASLR bypass, the combined risk escalates sharply. Organizations that treat this as a low-impact isolated issue could be setting themselves up for trouble if another vulnerability emerges.

What to Do Today: Patching, Testing, Hardening

1. Find your SQL Server 2025 instances and check the build.
Run this query in SQL Server Management Studio or any client:

SELECT @@VERSION;

Compare the result against the fixed builds: 17.0.4060.2 for CU installations, 17.0.1125.2 for GDR installations. If the version number is lower, you need to patch.

2. Apply the update that matches your servicing branch.
Download KB5101346 (CU) or KB5102333 (GDR) from the Microsoft Update Catalog, or use Windows Update/WSUS if your SQL Server receives patches that way. The packages are cumulative, so you don’t need to install earlier security updates first.

3. Test linked‑server setups that use MSDASQL.
Microsoft documents a known issue specific to KB5101346: queries that employ the MSDASQL OLE DB Provider for ODBC Drivers and include a provider string may fail with error 7416 after the update. Before deploying to production, verify any linked servers that rely on that provider. You may have to adjust provider strings or switch to a different OLE DB provider, such as the native SQL Server Native Client. At the time of writing, no fix for this regression is available, so testing is essential.

4. Tighten access controls.
Patching eliminates the pointer leak, but you should also reduce the odds of an attacker gaining any authenticated foothold. Consider these steps:
- Disable the sa login if it’s still active.
- Remove unused database logins and application accounts.
- Review permissions for all accounts to enforce true least privilege—can each account do only what it absolutely needs?
- Check firewall rules and cloud security groups to ensure SQL Server isn’t reachable from the public internet unless there’s a compelling business reason.
These measures won’t erase the vulnerability, but they shrink the pool of attackers who can exploit it—and they make subsequent lateral movement harder.

5. Watch for signs of exploitation.
No public exploit code has surfaced yet, but the situation could change. Monitor the Microsoft Security Response Center advisory for any updates on active attacks. In the meantime, set up alerts for unusual SQL Server activity: spikes in failed logins, connections from unfamiliar IP addresses, or anomalous numbers of metadata queries that might indicate a pointer-gathering attempt.

What Comes Next

CVE-2026-54116 is a reminder that information leaks can be just as valuable to attackers as direct code execution. The patch is simple to apply, but the broader lesson is about defense-in-depth. Patching should go hand in hand with configuration hygiene: restrict who can talk to your database servers, isolate low-privilege accounts, and assume that any stored credential will eventually be compromised.

If a future SQL Server bulletin ever tags a memory-corruption bug with “ASLR bypass via CVE-2026-54116 included,” we’ll know someone successfully chained these together in the wild. For now, applying the July 2026 security releases is the best way to keep that scenario off your servers.