Microsoft SQL Server EUVD-2026-100615

Exploitation requires the attacker to already possess an authorized, low-privileged account with local access to the SQL Server host or instance (AV:L, PR:L) - this is not remotely exploitable by an unauthenticated attacker. The attacker must send specially crafted input that reaches the vulnerable heap-allocation code path and reliably control heap layout to achieve code execution; the High attack complexity (AC:H) reflects this non-deterministic heap-grooming requirement, which meaningfully limits reliable exploitation. No end-user interaction is needed (UI:N). Affected deployments are specific build ranges of SQL Server 2019, 2022, and 2025 (per EUVD); instances already patched to the listed fixed builds (e.g., 15.0.4500.2, 16.0.4305.5, 17.0.5015.4) are not exploitable. The primary limiting factor is the prerequisite of local authenticated access, making shared/multi-tenant database hosts the realistic risk surface.

This is a moderate-priority issue rather than an emergency. The CVSS 3.1 vector (AV:L/AC:H/PR:L/UI:N) is internally consistent with the description's 'authorized attacker elevates privileges locally': it requires local access, existing low-level authentication (PR:L), and high attack complexity (AC:H) - the latter being typical of heap-based buffer overflow exploitation, which depends on heap grooming and layout control. The high-impact triad (C:H/I:H/A:H) yields the 7.0 (High) score, but the real-world risk is tempered by the local vector and the need for pre-existing authorized access to the SQL Server host/instance. No EPSS score is provided, no CISA KEV listing is present, and no public exploit code is referenced, so there is no evidence of active or imminent widespread exploitation. The signals are not conflicting - they consistently describe a post-authentication local privilege-escalation primitive that an attacker would chain after an initial foothold, not an internet-facing remote code execution flaw. Prioritize patching on multi-tenant or shared database servers where lower-privileged principals coexist with sensitive instances, but this does not warrant the same urgency as an unauthenticated network-exploitable bug.

An attacker who already holds a low-privileged authenticated account on a SQL Server host sends crafted input that overflows a heap buffer within the SQL Server process, corrupting heap metadata or adjacent objects to hijack execution and elevate to the SQL Server service (or higher) privilege level. Because AC is High, the attacker must reliably control heap layout, making exploitation non-trivial. No public proof-of-concept is identified at time of analysis, so weaponization effort remains on the attacker.