CVE-2025-24495: Intel Core Ultra Information Disclosure

CVE-2025-24495 Overview

CVE-2025-24495 affects the branch prediction unit (BPU) in some Intel Core Ultra Processors. The flaw stems from incorrect initialization of a microarchitectural resource. An authenticated local user can exploit this condition to potentially obtain sensitive information across security boundaries. Intel published the issue through advisory SA-01322, and Debian followed with a microcode update notice for Long Term Support users.

The vulnerability falls under the Information Disclosure and Side Channel Attack categories. It requires local access and low privileges, but exploitation complexity is high and depends on specific attack prerequisites. Successful exploitation impacts confidentiality without affecting integrity or availability.

Critical Impact
An authenticated local user on an affected Intel Core Ultra system can leverage transient execution behavior in the branch prediction unit to read confidential data outside the current security domain.

Affected Products

Intel Core Ultra Processors (subset enumerated in Intel advisory SA-01322)
Systems running affected Intel microcode without the May 2025 update
Debian LTS systems prior to the May 2025 intel-microcode patch

Discovery Timeline

2025-05-13 - CVE-2025-24495 published to NVD
2025-05-13 - Intel publishes Security Advisory SA-01322
May 2025 - Debian LTS releases corresponding microcode update
2026-04-15 - Last updated in NVD database

Technical Details for CVE-2025-24495

Vulnerability Analysis

The defect resides in the branch prediction unit of affected Intel Core Ultra Processors. The BPU does not correctly initialize an internal resource at the boundaries between execution contexts. State left behind from a prior context can influence speculative execution in a subsequent context. An attacker can observe microarchitectural side effects to infer the contents of that residual state.

The issue is a transient execution side channel similar in class to prior branch predictor data sampling and Branch History Injection issues. It does not allow arbitrary code execution and does not modify data. Confidentiality is the only directly impacted property, but the leaked information can include cryptographic keys, kernel memory, or data belonging to other processes.

Root Cause

The root cause is incorrect initialization of a resource inside the branch prediction unit. When the processor transitions across privilege levels or address spaces, the predictor structure retains state that should have been cleared or partitioned. Subsequent speculative branches can then act on attacker-influenced or victim-derived data and leave measurable cache or timing footprints.

Attack Vector

Exploitation requires local code execution rights on the target system, such as a low-privileged user account or a sandboxed workload. The attacker prepares the branch predictor in a controlled state, induces a transition into a higher-privileged or cross-domain context, and then measures microarchitectural side effects. No verified public proof-of-concept is currently available, and exploitation has not been observed in the wild. The attack complexity is high and requires attack prerequisites tied to the specific microarchitecture.

No verified exploit code is publicly available. Refer to the Intel Security Advisory SA-01322 for technical details about the affected hardware behavior.

Detection Methods for CVE-2025-24495

Indicators of Compromise

No file-based or network-based indicators exist for this hardware side channel
Successful exploitation leaves no log entries in conventional operating system telemetry
Detection focuses on patch state rather than runtime artifacts

Detection Strategies

Inventory processor models and microcode revisions across the estate and compare against the list in Intel advisory SA-01322
Audit BIOS/UEFI firmware versions to confirm vendor microcode bundles include the May 2025 fix
On Linux, verify the running microcode through /proc/cpuinfo and the microcode_ctl package version
Flag systems still reporting pre-patch microcode revisions for remediation

Monitoring Recommendations

Track Intel microcode advisories and OEM BIOS release notes for affected SKUs
Monitor for unexpected execution of low-level timing or cache-measurement utilities on production hosts
Alert on unauthorized local user creation or sandbox escapes, since exploitation requires local access
Correlate endpoint telemetry with firmware inventory data to identify lagging patch coverage

How to Mitigate CVE-2025-24495

Immediate Actions Required

Apply the Intel microcode update referenced in advisory SA-01322 to all affected Intel Core Ultra systems
Install the OS-level microcode package, such as Debian's May 2025 intel-microcode update, where BIOS updates are not yet available
Restrict local and interactive access on multi-tenant systems to trusted accounts only
Prioritize remediation on shared-tenancy hosts, developer workstations, and virtualization hosts

Patch Information

Intel addressed CVE-2025-24495 through a microcode update distributed in Intel Security Advisory SA-01322. Linux distributions are shipping the update through their microcode packages, including the Debian LTS Announcement May 2025. Apply the update via BIOS/UEFI firmware from the system OEM or through the operating system's microcode package, then reboot to activate the new microcode revision.

Workarounds

No software-only workaround fully mitigates the issue without the microcode update
Limit untrusted local code execution, including sandboxed JavaScript and container workloads, on unpatched hosts
Disable simultaneous multithreading (SMT) on highly sensitive systems if microcode cannot be applied immediately
Segregate sensitive workloads onto patched hardware until all systems are updated

bash

# Verify microcode revision on Linux after applying the update
grep -m1 'microcode' /proc/cpuinfo
dmesg | grep -i microcode
apt-get update && apt-get install --only-upgrade intel-microcode