Windows ALPC CVE-2026-69834

Exploitation requires the attacker to have an active low-privilege local process on the target Windows machine (PR:L), achievable via any standard domain or local user account or a previously established foothold. ALPC is a core Windows kernel component enabled in all configurations and cannot be disabled; no special feature flag or non-default configuration is required to expose the vulnerable code path. The key limiting condition is AC:H: reliable exploitation requires winning a race condition or performing precise kernel heap manipulation, which demands attacker skill and may fail unpredictably. There is no network-based attack vector - the attacker must execute code locally. Remote-only threat actors must first achieve local execution through a separate vulnerability or social engineering before this flaw is reachable.

The CVSS 7.0 score reflects the combination of high local impact (C:H/I:H/A:H) tempered by AV:L and AC:H, which together substantially reduce exploitability compared to a network-reachable flaw. In practice, ALPC UAF vulnerabilities are among the most operationally significant Windows LPE classes - they are regularly chained after an initial foothold (phishing, web exploit) to achieve SYSTEM or beyond, making patch prioritization important for any Windows fleet; even a mid-sized IT operation should treat this as urgent given the breadth of affected versions. EPSS data is absent from the input so exploitation probability cannot be quantified precisely, but historical patterns for Windows ALPC LPE CVEs show consistent interest from threat actors using them as post-exploitation primitives. No active exploitation is confirmed (not in CISA KEV), and no public POC is identified, which is the primary signal distinguishing this from an emergency-tier vulnerability at the time of analysis. The AC:H rating is the key limiting factor: reliable exploitation requires defeating heap-layout non-determinism, which raises the skill floor and limits opportunistic automated exploitation. The extremely broad affected version range - from legacy Server 2012 to the latest Server 2025 builds - means the aggregate exposed surface is large even if per-host exploitation difficulty is moderate.

An attacker who has obtained initial code execution as a standard Windows user - for example, via a phishing payload or browser exploit - triggers a race condition in the ALPC kernel subsystem to free a port object while holding a reference, then carefully grooms kernel heap memory to control the freed region. Upon successful UAF dereference, the attacker achieves kernel code execution and elevates to SYSTEM, enabling credential harvesting, persistence, or lateral movement. No public POC has been identified at time of analysis; exploitation requires non-trivial race-condition timing skill.