CVE-2025-47997: SQL Server Race Condition Info-Disclosure — Patch Now

Microsoft Security Response Center (MSRC) advisory describes CVE-2025-47997 as a concurrency (race‑condition) information‑disclosure flaw in Microsoft SQL Server that can be triggered by an authorized user and may allow sensitive memory or data to be leaked over the network; administrators should treat the advisory as authoritative, verify affected builds in their estate, and apply vendor-supplied updates immediately. (msrc.microsoft.com)

Background / Overview​

Microsoft’s update guide entry for CVE-2025-47997 identifies the root cause as concurrent execution using a shared resource with improper synchronization (a race condition) inside SQL Server. That class of bug typically allows two or more threads to access and modify the same internal state without correct coordination, producing windows in which privileged internal data can be read or returned to a caller that should not see it. The net effect for SQL Server is an information‑disclosure condition: an authorized account that can run queries or connect to a vulnerable handler may receive data from memory that was not intended for the caller. (msrc.microsoft.com)
Operationally this matters because SQL Server often:

• Hosts sensitive business data and secrets (connection strings, tokens).
• Runs under service accounts with broad privileges.
• Is trusted by other systems and applications on the network.

When a leak like this is possible, exposure can be limited to SQL‑level objects or, if combined with other flaws, escalate to credential theft or host‑level compromise. Multiple independent mid‑2025 advisories and vendor writeups covering SQL Server grouped information‑disclosure, privilege‑escalation, and memory‑corruption fixes into the same patch cycle, underscoring that these classes of bugs are often related and can be chained in real incidents.

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What the advisory says (concise technical summary)​

• Vulnerability type: Information disclosure due to race condition / improper synchronization in SQL Server internals. (msrc.microsoft.com)
• Attack vector: Network — the vulnerability is exploitable over the wire by an account that can interact with the vulnerable SQL Server surface. (msrc.microsoft.com)
• Attacker privileges: Authorized (requires some SQL login or an account able to send the relevant requests), which lowers the bar in environments where application/service accounts or third‑party integrations hold credentials.
• Impact: Disclosure of memory or sensitive data; disclosure may enable follow‑on steps like credential harvesting or privilege escalation when chained with other vulnerabilities.

Important verification note: the MSRC entry you provided is the canonical vendor statement for this CVE and must be consulted for the exact list of affected builds and KB patch identifiers. Public CVE indexes and vendor trackers sometimes lag or index similar SQL Server CVEs (for example, CVE‑2025‑49717/49718/49719 in the same July 2025 patch cycle), so cross‑mapping MSRC → KB → build is the safest path for remediation. (support.microsoft.com)

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Why a race condition in a database engine is dangerous​

Race conditions in complex server software like SQL Server can expose data that sits in memory buffers during legitimate operations. Unlike classic SQL injection or broken authentication, concurrency bugs:

• Can leak uninitialized memory or data from other sessions without directly executing attacker-supplied SQL.
• May be triggered by carefully timed, legitimate‑looking operations rather than obviously malicious payloads.
• Are often non‑deterministic and harder to detect in testing (they depend on timing), which increases the chance the bug persisted unnoticed in production builds.

Real‑world consequences include exposure of connection strings, credentials, encryption keys, query results from other sessions, and internal state that can be used in follow‑on attacks such as lateral movement or ransomware staging. The July 2025 patch cycle demonstrated how information disclosure, buffer overflows, and EoP (elevation of privilege) issues in SQL Server frequently appear together and should be treated as a single operational priority.

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Cross‑verification and the CVE identifier ambiguity​

A careful cross‑check of public trackers reveals a practical problem administrators face during fast patch cycles: the same vendor update window may include multiple related CVEs and occasionally CVE identifiers appear differently across feeds. Microsoft’s MSRC entry you linked is authoritative for CVE‑2025‑47997, but third‑party summaries of the same patch window prominently list CVE‑2025‑49717, CVE‑2025‑49718 and CVE‑2025‑49719 as the SQL Server fixes released on July 8, 2025. That means:

• Use the MSRC advisory and Microsoft KB pages first to map CVE → KB → exact fixed builds for your SQL Server versions. (msrc.microsoft.com, support.microsoft.com)
• If an external scanner reports a different CVE string for the same symptom, capture the scanner evidence and reconcile it against the vendor KB — misattribution of identifiers is common during rapid CVE propagation.

Because public indexes sometimes show different CVE numbers for related fixes, admins must not rely solely on CVE string matching; instead match the exact product, build number and KB article listed in Microsoft’s Update Guide.

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Affected products and patch availability (what to check now)​

Microsoft generally lists fixed builds and KB details on the same days it publishes cumulative updates. For the mid‑2025 SQL Server updates that remedied multiple information‑disclosure and memory‑safety flaws, Microsoft published per‑release KB articles (example KB entries for 2019 and 2022 CUs are available) — administrators should check the KB for their exact product branch (SQL Server 2016 SP3, 2017, 2019, 2022, GDR and CU channels). Confirm:

• Exact SQL Server product version (SELECT @@VERSION or check the SQL Server error log).
• Whether your instance is on the GDR or CU servicing channel.
• If companion client components (ODBC/OLE DB drivers) are listed as affected — driver updates are sometimes required to maintain compatibility after engine fixes. (support.microsoft.com)

Vendor and community guidance issued in July 2025 emphasized that the fixed builds were rolled into cumulative updates on July 8, 2025; those KB entries list the fixed product versions. If you cannot locate CVE‑2025‑47997 in public trackers, the MSRC KB entries remain the definitive remediation mapping. (support.microsoft.com)

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Exploitability, proof‑of‑concepts, and real‑world risk​

• Exploit complexity: Race‑condition exploitation generally requires precise timing and may be harder than simple injection—however, authorized access to SQL Server significantly lowers the bar because the attacker already can send requests that exercise internal code paths. Vendors that analyzed the July 2025 fixes judged exploitation likelihood variably; Microsoft’s own exploitability ratings are the primary source for that assessment. When information about an exploit exists in the wild, urgency increases dramatically.
• Public PoC: At the time of the vendor’s advisory, there were no widely‑distributed, weaponized public proof‑of‑concepts specifically attributed to CVE‑2025‑47997; cross‑referenced SQL Server bugs in July 2025 (e.g., the uninitialized‑memory leak CVE‑2025‑49719) were described as a publicly disclosed zero‑day in some summaries but without confirmed exploit code. Treat any internet chatter claiming a working exploit as unverified until multiple reputable sources confirm. (helpnetsecurity.com, action1.com)

Cautionary flag (unverifiable claim): The CVE string you provided does appear on MSRC, but some major vulnerability trackers and vendor roundups index the related SQL Server fixes under different CVE numbers for the same July 8, 2025 patch cycle. That inconsistency is typically a propagation or indexing issue; it should not delay patching. Rely on Microsoft’s KB/build numbers for remediation mapping.

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Immediate operational playbook (0–24 hours)​

• Confirm whether SQL Server instances in your estate match the fixed builds listed in Microsoft’s KB for the advisory. Do not rely only on CVE strings — match product, build, and KB. (support.microsoft.com)
• If any instance is listed as vulnerable or you cannot verify quickly: block external access to SQL Server ports (TCP 1433, UDP 1434) at the perimeter until patches are applied. Use network ACLs or host firewalls.
• Prioritize internet‑facing and DMZ‑adjacent SQL Server hosts, and those used by high‑value applications (auth servers, payment stacks, admin consoles).
• Schedule the vendor KB patch per your change control process: stage in a test ring, validate app compatibility (especially if KB requires OLE DB/driver updates), then push to production. Balbix and other vendors noted that some driver versions must be updated to maintain compatibility with the engine fixes. (balbix.com)
• If patching is delayed for technical reasons, implement compensating controls: network segmentation, strict firewalling limiting access to only necessary application tiers, rotation of service credentials, and enhanced logging/auditing.

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Medium‑term mitigation and hardening (1–14 days)​

• Apply the Microsoft cumulative update that contains the fix and update companion drivers (OLE DB/ODBC) if Microsoft’s advisory requires them. Test carefully — driver updates sometimes require application validation. (support.microsoft.com, balbix.com)
• Enforce least privilege: review service accounts and application logins, removing sysadmin rights where not strictly necessary. Move application accounts to scoped, least‑privilege roles.
• Audit and reduce surface area: disable named protocols (Named Pipes, VIA) if not required; close unused ports; avoid exposing SQL endpoints directly to untrusted networks.
• Strengthen application layer: use parameterized queries, ORMs, or stored procedures to minimize the chance that application inputs reach lower‑level server internals in unsafe formats. While this particular CVE is concurrency‑related, robust input handling reduces the likelihood of chained attacks.

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Detection, logging and hunting guidance​

Collect and monitor this telemetry aggressively during the remediation window:

• SQL Server Audit / Extended Events: track creation of logins, server role changes, ALTER SERVER ROLE events, and calls to high‑privilege procedures (xp_cmdshell, sp_addsrvrolemember). These are common detection points for attackers abusing escalated SQL privileges or trying to persist. Example hunt queries to find newly‑elevated principals are routine and should be scheduled.
• Network telemetry: inspect client IPs that submit unusual stacked queries or sequences with EXEC sp_executesql and large payloads; flag queries originating from unexpected application hosts.
• Endpoint and EDR: look for abnormal process launches from sqlservr.exe or sudden creation of scheduled tasks / services on database hosts following suspicious SQL activity. Capture volatile memory for forensic analysis if you suspect exploitation.

Recommended quick DBA check (example):

• Enumerate server principals with sysadmin membership:
  SELECT p.name, p.type_desc FROM sys.server_principals p JOIN sys.server_role_members m ON p.principal_id = m.member_principal_id JOIN sys.server_principals r ON m.role_principal_id = r.principal_id WHERE r.name = 'sysadmin';
• Run this before and after applying patches to detect unexpected elevation activity.

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Testing patch and compatibility notes​

• Stage patches in a controlled environment and test critical application workflows. Some provider guidance from July 2025 noted that driver updates may be required (Microsoft OLE DB Driver for SQL Server v18.7+ recommended for certain fixes), and upgrades in high‑throughput environments should be tested for performance/regression. (balbix.com, support.microsoft.com)
• Back up databases and configuration before applying cumulative updates. Validate backup/restoration workflows after patching to ensure recoverability in case of unexpected behavior.

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Risk assessment and priorities for different environments​

• Highest risk: internet‑facing SQL Server instances, environments with weak segmentation, and systems where application/service accounts have excessive permissions. Prioritize these for immediate mitigation.
• Medium risk: internal production databases that are reachable by many services or host credentials used across multiple systems. These are attractive lateral movement stepping stones.
• Lower risk (but still needing attention): isolated dev/test systems behind strict segmentation — still patch per policy because attackers often pivot from less‑protected dev environments.

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Strengths and limitations of vendor and community guidance​

Strengths:

• Microsoft’s MSRC and KB pages provide authoritative mappings of CVEs to fixed builds and KB numbers — this is the primary source for remediation priorities. (msrc.microsoft.com, support.microsoft.com)
• Community and vendor writeups consolidate practical mitigations (network isolation, driver compatibility notes, detection queries), which accelerate operational response.

Limitations and risks:

• CVE propagation lag and misattribution between MSRC, NVD and third‑party feeds can create confusion for patch managers; always map to Microsoft KB/build numbers rather than CVE strings alone.
• Public disclosure of technical details can accelerate exploit development; defenders must close the patch window quickly once details are known.

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Recommended checklist (actionable summary)​

• Immediately: confirm affected builds using Microsoft’s Update Guide entry for CVE‑2025‑47997 and associated KBs; if confirmed, schedule and apply the cumulative update. (msrc.microsoft.com, support.microsoft.com)
• If patching will be delayed: block SQL Server network exposure to untrusted networks, restrict access to application tiers only, and rotate service credentials.
• After patching: validate application compatibility, update companion drivers (OLE DB/ODBC) where advised, and monitor SQL Server audit logs for anomalous activity. (balbix.com)
• Hunt: run the sysadmin enumeration query and monitor for unexpected role changes, new logins, or calls to elevated stored procedures. Preserve logs and collect forensic artifacts if you see suspicious changes.

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Final analysis and closing assessment​

CVE‑2025‑47997 is a serious information‑disclosure race condition in Microsoft SQL Server that must be handled as a high operational priority for database owners and platform teams. While race‑condition exploits are sometimes complex, the requirement for authorized access coupled with SQL Server’s privileged position on most networks elevates the real‑world risk — particularly where application or service accounts have more permissions than necessary or where instances are exposed to weaker trust zones.
Because CVE identifiers and third‑party feeds can differ during rapid remediation cycles, the correct operational approach is clear: treat Microsoft’s MSRC/KB guidance as the authoritative source, map your instances by build numbers to the vendor’s fixed builds, and apply the cumulative updates (and any companion driver updates) promptly. Compensating controls — network isolation, least privilege, credential rotation, and enhanced logging — should be applied wherever immediate patching is infeasible.
Practical, prioritized steps are: verify builds against the MSRC advisory, stage-and‑patch CUs, update OLE DB/ODBC drivers if required, tighten network access and permissions, and hunt for anomalous privilege changes and suspicious SQL activity. These actions close the most feasible attack paths and detect attempted exploitation during the remediation window. (msrc.microsoft.com, support.microsoft.com)
Conclusion: apply the vendor patches per the MSRC/KB guidance without delay, reconcile any CVE identifier mismatches by matching the KB/build metadata, and harden detection and network controls to reduce exposure during the rollout.

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Source: MSRC Security Update Guide - Microsoft Security Response Center