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CVE PROGRAM SOURCE RECORDUnscored

CVE-2026-31521

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

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Status
Published
Published
Updated
Assigning organization
Linux

Description

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 < symsec->sh_size / sizeof(Elf_Sym); i++) { const char *name = info->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->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/

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < 5d16f519b6eb1d071807e57efe0df2baa8d32ad6affected
  • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < 4bbdb0e48176fd281c2b9a211b110db6fd94e175affected
  • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < 082f15d2887329e0f43fd3727e69365f5bfe5d2caffected
  • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < ec2b22a58073f80739013588af448ff6e2ab906faffected
  • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < ef75dc1401d8e797ee51559a0dd0336c225e1776affected
  • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < 6ba6957c640f58dc8ef046981a045da43e47ea23affected
  • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < f9d69d5e7bde2295eb7488a56f094ac8f5383b92affected

Linux Linux

Default version status: affected

  • 2.6.12affected
  • 0 to < 2.6.12unaffected
  • 5.15.203 to ≤ 5.15.*unaffected
  • 6.1.168 to ≤ 6.1.*unaffected
  • 6.6.131 to ≤ 6.6.*unaffected
  • 6.12.80 to ≤ 6.12.*unaffected
  • 6.18.21 to ≤ 6.18.*unaffected
  • 6.19.11 to ≤ 6.19.*unaffected
  • 7.0 to ≤ *unaffected

References