CVE-2025-35973: Intel Processors Privilege Escalation Flaw

CVE-2025-35973 Overview

CVE-2025-35973 is a privilege escalation vulnerability affecting some Intel(R) Processors. The flaw stems from improper handling of values within Ring 0 execution contexts, including kernel, hypervisor, and bare metal operating system code. An authorized adversary with privileged local access can leverage this issue through a high-complexity attack to escalate privileges further. The vulnerability is classified under [CWE-229] (Improper Handling of Values) and requires special internal knowledge to exploit successfully.

Critical Impact
Successful exploitation may lead to high-impact compromise of downstream system confidentiality and integrity, despite low direct impact on the vulnerable component itself.

Affected Products

Some Intel(R) Processors (specific models enumerated in Intel Security Advisory SA-01428)
Ring 0 execution contexts: Kernel components
Hypervisor and Bare Metal Operating System environments

Discovery Timeline

2026-08-11 - CVE-2025-35973 published to the National Vulnerability Database
2026-08-12 - Last updated in NVD database

Technical Details for CVE-2025-35973

Vulnerability Analysis

The vulnerability affects how certain Intel processors handle values during operations executed in Ring 0. Ring 0 represents the most privileged execution level on x86 architectures, encompassing kernel code, hypervisor code, and bare metal operating system routines. When these highly privileged components process specific values improperly, the resulting behavior can be leveraged by an already-privileged adversary to gain additional privileges.

Because the attack requires local access, a privileged account, and high complexity, exploitation is not trivial. Adversaries need specific internal knowledge of processor behavior and target conditions. The direct impact on the vulnerable component is limited, but the subsequent impact on connected systems reaches high levels for confidentiality and integrity.

Root Cause

The root cause is improper handling of values ([CWE-229]) inside privileged execution contexts on affected Intel processors. When Ring 0 code operates on certain values without appropriate validation or bounds enforcement, the processor state can be manipulated in ways that break the isolation guarantees expected between the kernel, hypervisor, and downstream workloads.

Attack Vector

Exploitation requires local access with an existing privileged user context. The adversary must combine that access with a high-complexity attack sequence that depends on specific runtime conditions being present. No user interaction is required. Because this vulnerability sits at the processor level within Ring 0, successful exploitation can cross trust boundaries into hypervisor-managed guests or other kernel-protected resources. Refer to the Intel Security Advisory SA-01428 for processor-specific technical details.

No public proof-of-concept code or verified exploitation examples are available at this time.

Detection Methods for CVE-2025-35973

Indicators of Compromise

No public indicators of compromise are currently documented for CVE-2025-35973.
Monitor for unexpected privilege transitions from kernel-mode processes or hypervisor components.
Track anomalous behavior in bare metal workloads that suggests Ring 0 state manipulation.

Detection Strategies

Baseline normal kernel and hypervisor behavior, then alert on deviations from established execution patterns.
Correlate local privileged account activity with subsequent lateral movement or credential access events.
Deploy processor microcode telemetry where available to identify anomalies tied to Intel's advisory guidance.

Monitoring Recommendations

Audit privileged account usage on systems running affected Intel processors and hypervisor platforms.
Monitor firmware and BIOS/UEFI update compliance across the fleet to confirm mitigation deployment.
Log hypervisor guest escape indicators, including unexpected VM exits or MSR access patterns.

How to Mitigate CVE-2025-35973

Immediate Actions Required

Review the Intel Security Advisory SA-01428 to identify affected processor models in your environment.
Apply vendor-provided microcode updates and BIOS/UEFI firmware releases from your hardware manufacturer.
Restrict local privileged access to systems running affected processors until mitigations are deployed.

Patch Information

Intel published mitigation guidance in Security Advisory SA-01428. Consult your OEM (Dell, HPE, Lenovo, Supermicro, or others) for microcode and firmware updates that incorporate Intel's fix. Hypervisor vendors typically release corresponding platform updates that consume the microcode change; review your hypervisor vendor's security bulletins for redistribution timelines.

Workarounds

Limit the number of accounts with Ring 0 or hypervisor administrative privileges to reduce the population of potential adversaries.
Segment hypervisor management networks from tenant and workload networks to constrain lateral movement.
Enforce strict change control on kernel modules and hypervisor extensions to reduce unauthorized code paths reaching Ring 0.

bash

# Verify installed microcode version on Linux systems
grep -m1 'microcode' /proc/cpuinfo

# Check current CPU model against Intel SA-01428 affected list
cat /proc/cpuinfo | grep 'model name' | uniq

# On systems using intel-microcode package, confirm latest version is applied
dmesg | grep -i microcode