Bounds Check Bypass in Linux Kernel Affects Module Loader Functionality

CVE-2026-31521

What is CVE-2026-31521?

A vulnerability in the Linux kernel arises from the module loader's failure to validate the bounds of the ELF section index during symbol simplification. Specifically, when accessing symbols in the ELF section, an out-of-bounds symbol table index, such as 0xffff, can lead to a kernel panic. This condition can occur either from legitimate use cases or due to corruption. The oversight permits exploitation that can result in system instability or crashes. A patch has been introduced to enforce bounds checking on the symbol index to prevent this dangerous flaw from causing fatal exceptions.

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