Improper Validation of Specified Index, Position, or Offset in Input Affecting bpftool-debuginfo package, versions <1:6.1.168-202.320.amzn2023


Severity

Recommended
high

Based on Amazon Linux security rating.

Threat Intelligence

EPSS
0.01% (3rd percentile)

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  • Snyk IDSNYK-AMZN2023-BPFTOOLDEBUGINFO-16626458
  • published10 May 2026
  • disclosed22 Apr 2026

Introduced: 22 Apr 2026

NewCVE-2026-31521  (opens in a new tab)
CWE-1285  (opens in a new tab)

How to fix?

Upgrade Amazon-Linux:2023 bpftool-debuginfo to version 1:6.1.168-202.320.amzn2023 or higher.
This issue was patched in ALAS2023-2026-1681.

NVD Description

Note: Versions mentioned in the description apply only to the upstream bpftool-debuginfo package and not the bpftool-debuginfo package as distributed by Amazon-Linux. See How to fix? for Amazon-Linux:2023 relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

module: Fix kernel panic when a symbol st_shndx is out of bounds

The module loader doesn't check for bounds of the ELF section index in simplify_symbols():

   for (i = 1; i &lt; symsec-&gt;sh_size / sizeof(Elf_Sym); i++) {
    const char *name = info-&gt;strtab + sym[i].st_name;

switch (sym[i].st_shndx) {
case SHN_COMMON:

[...]

default:
    /* Divert to percpu allocation if a percpu var. */
    if (sym[i].st_shndx == info-&amp;gt;index.pcpu)
        secbase = (unsigned long)mod_percpu(mod);
    else

/** HERE --> **/ secbase = info->sechdrs[sym[i].st_shndx].sh_addr; sym[i].st_value += secbase; break; } }

A symbol with an out-of-bounds st_shndx value, for example 0xffff (known as SHN_XINDEX or SHN_HIRESERVE), may cause a kernel panic:

BUG: unable to handle page fault for address: ... RIP: 0010:simplify_symbols+0x2b2/0x480 ... Kernel panic - not syncing: Fatal exception

This can happen when module ELF is legitimately using SHN_XINDEX or when it is corrupted.

Add a bounds check in simplify_symbols() to validate that st_shndx is within the valid range before using it.

This issue was discovered due to a bug in llvm-objcopy, see relevant discussion for details [1].

[1] https://lore.kernel.org/linux-modules/20251224005752.201911-1-ihor.solodrai@linux.dev/

CVSS Base Scores

version 3.1