Buffer Overflow Vulnerability in MCUBoot Affecting Firmware Updates

CVE-2026-127916

What is CVE-2026-127916?

A buffer overflow vulnerability exists in MCUBoot that allows for improper handling of image header sizes during firmware updates. When certain conditions are met, an image can be hashed without adequate bounds checks, leading to potential memory over-reads during validation processes. This can cause critical issues such as the inability to boot the device if a malformed firmware image is uploaded. The vulnerability is exacerbated when using flash backends that do not impose enough boundaries during read operations. The patch addresses this by ensuring proper checks on image sizes before any hashing occurs, thus securing the firmware update mechanism.

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