Description

Memory corruption while processing a crafted ELF file in the Primary Bootloader.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "6.9",
  "pubDate": "2026-09-22T10:17:08.973Z",
  "pubdate": "2026-09-22T10:17:08.973Z",
  "executiveSummary": "This vulnerability involves a memory corruption flaw within the Primary Bootloader during the parsing of malformed Executable and Linkable Format (ELF) files.\nThe vulnerability is categorized as a memory safety issue, likely stemming from improper validation of ELF header fields or section headers.\nSuccessful exploitation allows an attacker to achieve arbitrary code execution or cause a system denial-of-service by triggering a crash during the early boot sequence.\nThe affected system is the Primary Bootloader, which operates at the highest privilege level (EL3 or equivalent) before the operating system kernel is initialized.\nThe attack is characterized by the need for an attacker to supply a crafted ELF image, typically via physical access or peripheral-based loading mechanisms.\nDue to the early execution context, exploitation bypasses standard OS-level security controls, effectively granting the attacker control over the platform's root of trust.\nThe risk implication is severe, as compromise of the Primary Bootloader allows for persistent firmware implants and the subversion of subsequent security chain-of-trust components.",
  "technicalDetails": "The vulnerability resides in the parsing logic of the Primary Bootloader responsible for processing ELF files, which are frequently used for loading secondary stages or firmware binaries. The root cause is an insufficient bounds check or integer validation when interpreting metadata fields within the ELF structure, such as the 'e_phoff' (program header table offset), 'e_phnum' (number of program header entries), or section-specific 'sh_size' and 'sh_offset' values.\nWhen the bootloader encounters a crafted ELF file, it reads these metadata fields into memory without validating that the specified offsets or sizes remain within the allocated buffer boundaries. By providing malformed values, an attacker can trigger an out-of-bounds write operation, potentially overwriting adjacent memory regions within the bootloader's address space. In the context of a low-level boot environment, this often occurs in SRAM or tightly coupled memory where security boundaries are minimal or non-existent.\nThe exploitation flow initiates when the bootloader parses the malicious file. Upon encountering the crafted header, the internal logic incorrectly calculates the target memory address for a data copy or structural update. If the attacker can control the contents of the 'data' segments within the ELF file, they can inject malicious code or overwrite return addresses on the stack. Because the Primary Bootloader typically executes with unrestricted access to the SoC and peripheral registers, an attacker can overwrite internal pointers to hijack the instruction pointer (IP/PC).\nGiven that this vulnerability occurs before the MMU or IOMMU are fully configured or restrictive policies are enforced, the environment lacks Address Space Layout Randomization (ASLR), Data Execution Prevention (DEP), or stack canaries. Consequently, an attacker can reliably execute arbitrary machine code with the highest privilege level. This grants the attacker persistent control over the platform, allowing for the exfiltration of sensitive key material, the modification of hardware security configurations, or the installation of a persistent bootkit that survives OS-level reinstalls.\nThis vulnerability is particularly critical because it bypasses the secure boot chain. Even if the signature verification of the ELF file is nominally present, the memory corruption may be triggered during the parsing phase before or during the signature validation process, potentially bypassing the chain-of-trust checks entirely if the corruption impacts the verification logic itself."
}