# CVE-2026-20753: Intel Slim Bootloader integer overflow in UEFI firmware

Source: https://junglewise.ai/threats/cve-2026-20753-intel-slim-bootloader-integer-overflow-in-uefi-firmware  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-05-12. Updated: 2026-05-14  
License: CC BY 4.0 with a link back

CVE-2026-20753 · Severity: info · CVSS 8.7 · Published 2026-05-12

A vulnerability in the Intel Slim Bootloader, which is responsible for initializing hardware and launching the operating system, could allow an attacker to gain higher-level system privileges. An attacker who already has administrative access to the system software could exploit this flaw to execute unauthorized code at the firmware level. This could lead to a complete compromise of the system's security, including the ability to bypass operating system protections and access sensitive data.

Technologies: [Intel Slim Bootloader](https://junglewise.ai/threats/technologies/slim-bootloader). Vendors: [Intel](https://junglewise.ai/threats/vendors/intel).

## Quick answers

**Is CVE-2026-20753 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-20753 being exploited in the wild.

**How severe is CVE-2026-20753?** Informational severity, with a CVSS score of 8.7, published 12 May 2026.

**Which products and versions are affected?** Intel Slim Bootloader Versions prior to hash 193129e6a1ea675527670785c8c75ed09b423211 (01/22/2026).

**Is there a fix for CVE-2026-20753?** A patch was published on 2026-01-22: Date of the recommended firmware hash fix Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-20753 attacked?** It is attacked with local access, in device firmware.

**Am I affected by CVE-2026-20753?** Check whether you run Intel Slim Bootloader at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

An integer overflow vulnerability (CWE-190) exists within the UEFI firmware component of the Intel Slim Bootloader. The flaw is triggered during local access by a high-privileged system software adversary. By exploiting this overflow, an attacker can achieve local code execution within the firmware environment, bypassing higher-level security boundaries. The attack is characterized by low complexity but requires specific 'attack requirements' (preconditions) to be present. Intel has released a firmware update to mitigate this issue, identified by a specific commit hash from January 2026.

## Affected products

- Intel Slim Bootloader Versions prior to hash 193129e6a1ea675527670785c8c75ed09b423211 (01/22/2026)

## Timeline

- 2026-01-22: patched: Date of the recommended firmware hash fix
- 2026-05-12: disclosed: Initial release of Intel-SA-01425
- 2026-05-12: advisory: NVD publication date

## References

- [https://intel.com/content/www/us/en/security-center/advisory/intel-sa-01425.html](https://intel.com/content/www/us/en/security-center/advisory/intel-sa-01425.html)

## Related threats

- [Intel Slim Bootloader pointer dereference in FirmwareWakingVector](https://junglewise.ai/threats/cve-2026-50175-untrusted-pointer-dereference-in-the-firmwarewakingvector-for-the)
- [Intel Slim Bootloader Ext2 parser incorrect comparison](https://junglewise.ai/threats/cve-2026-44624-incorrect-comparison-in-the-ext2-parser-for-the-intel-r-slim)
- [Intel Slim Bootloader out-of-bounds write privilege escalation](https://junglewise.ai/threats/cve-2026-41224-out-of-bounds-write-in-the-uefi-firmware-for-the-intel-r-slim)
- [Intel Slim Bootloader integer overflow in UEFI firmware](https://junglewise.ai/threats/cve-2026-41221-integer-overflow-in-the-uefi-firmware-for-the-intel-r-slim)
- [Intel Slim Bootloader stack buffer overflow in Ring 0](https://junglewise.ai/threats/cve-2026-35500-stack-based-buffer-overflow-in-the-uefi-firmware-for-the-intel-r)