CVE-2026-25194 Overview
CVE-2026-25194 is an out-of-bounds write vulnerability [CWE-787] in the firmware for the Intel(R) Slim Bootloader. A local, privileged attacker can trigger the flaw to cause a denial of service on the affected system. The issue does not affect confidentiality or integrity and produces only a low availability impact on the vulnerable component. Intel documented the issue in Intel Security Advisory SA-01475.
Critical Impact
A privileged local adversary can trigger an out-of-bounds write in the Slim Bootloader firmware and cause a denial of service on the affected system.
Affected Products
- Intel(R) Slim Bootloader firmware (see Intel SA-01475 for versioning)
Discovery Timeline
- 2026-08-11 - CVE-2026-25194 published to NVD
- 2026-08-12 - Last updated in NVD database
Technical Details for CVE-2026-25194
Vulnerability Analysis
The vulnerability lives in the firmware of the Intel Slim Bootloader, a lightweight open-source bootloader used to initialize hardware and hand off control to a payload. An out-of-bounds write occurs when the bootloader writes data past the end of an allocated buffer during firmware execution. Because the flaw resides in pre-boot firmware, successful exploitation halts or destabilizes the boot process rather than yielding code execution or data exposure. Intel classifies the availability impact as low and confidentiality and integrity impact as none.
Root Cause
The root cause is improper bounds checking on a write operation inside a Slim Bootloader firmware routine, tracked as an out-of-bounds write weakness [CWE-787]. The firmware writes to a memory location outside the intended buffer boundary, corrupting adjacent memory used during early platform initialization. Intel Security Advisory SA-01475 covers the affected component and the fixed firmware version.
Attack Vector
Exploitation requires local access and high privileges on the target system. An attacker with system software or administrative-level access supplies input to the vulnerable firmware path, triggering the out-of-bounds write. No user interaction is required, and the attack complexity is low once the attack requirements are satisfied. The result is a denial of service condition affecting the availability of the vulnerable system.
No public proof-of-concept exploit is available for CVE-2026-25194, and it is not listed in the CISA Known Exploited Vulnerabilities catalog. Refer to the Intel Security Advisory SA-01475 for technical details on the affected firmware paths.
Detection Methods for CVE-2026-25194
Indicators of Compromise
- Unexpected system boot failures, hangs during firmware initialization, or repeated reboot loops on systems using Intel Slim Bootloader.
- Firmware or platform logs showing abnormal termination of the boot process without a clean transition to the payload.
Detection Strategies
- Inventory endpoints and embedded systems that use Intel Slim Bootloader firmware and compare installed versions against the fixed version referenced in Intel SA-01475.
- Correlate platform boot telemetry and hardware watchdog events with recent local privileged activity to identify attempts to trigger the out-of-bounds write.
Monitoring Recommendations
- Monitor privileged local access events, driver loads, and system software changes that could reach firmware interfaces on affected platforms.
- Track firmware version drift across the fleet through configuration management and endpoint telemetry to ensure patched builds are deployed.
How to Mitigate CVE-2026-25194
Immediate Actions Required
- Review Intel Security Advisory SA-01475 and identify systems running affected Slim Bootloader firmware versions.
- Apply the vendor-supplied Slim Bootloader firmware update to all impacted systems as it becomes available from platform manufacturers.
- Restrict administrative and system software privileges to reduce the pool of local accounts able to reach the vulnerable firmware code path.
Patch Information
Intel has published Intel Security Advisory SA-01475 addressing CVE-2026-25194. Consult the advisory for the specific fixed Slim Bootloader firmware version and vendor guidance on rebuilding or redeploying platform firmware images that embed Slim Bootloader.
Workarounds
- Enforce least privilege on all endpoints so that only trusted administrators hold the high privileges required for exploitation.
- Apply strict physical and logical access controls on systems where firmware updates cannot be immediately deployed, since exploitation requires local access.
# Configuration example
# Verify Slim Bootloader firmware version against the fixed release in Intel SA-01475
# Replace <tool> with your platform vendor's firmware inventory utility
<tool> --query firmware-version --component slim-bootloader
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
