ACPICA: Fix NULL pointer dereference in acpi_ns_custom_package()

Summary

In the Linux kernel, the following vulnerability has been resolved: ACPICA: Fix NULL pointer dereference in acpi_ns_custom_package() acpi_ns_custom_package() unconditionally dereferences the first element of the package to read the _BIX version number, without checking for NULL: if ((*Elements)->Common.Type != ACPI_TYPE_INTEGER) When firmware returns a _BIX package whose first element is an unresolvable reference, ACPICA evaluates that entry to NULL. acpi_ns_remove_null_elements() does not strip NULL entries for ACPI_PTYPE_CUSTOM packages (fixed-position format would break if elements were shifted), so acpi_ns_custom_package() sees the NULL and causes a crash. Add a NULL check for the first element (version field) before dereferencing it. The caller then receives AE_AML_OPERAND_TYPE instead of crashing.

Timeline

1. Sep 24, 2026, 4:04 PM UTCCVE published
2. Oct 3, 2026, 10:58 AM UTCRecord last updated

Affected versions

• Linux Linux

  From 7952d40240855932de01bbe81c02bf1416ec91d8 · fixed in fad537538cdfcdc51e41db61bbf9ebe5ed9427eb; From 7952d40240855932de01bbe81c02bf1416ec91d8 · fixed in 9936507ac0f2379787a2a805b11ab1cf0f241372; From 7952d40240855932de01bbe81c02bf1416ec91d8 · fixed in 644888605f55395e6012ed43e3ed643ef7ab5013; From 7952d40240855932de01bbe81c02bf1416ec91d8 · fixed in 08c5dee5da1d8d99b5a4e94db5a3d873c491771e; From 7952d40240855932de01bbe81c02bf1416ec91d8 · fixed in 3762c6c8ae5073892d7cec736cc54270c7c9ce90; From 7952d40240855932de01bbe81c02bf1416ec91d8 · fixed in 3cbf096a478f4fa03953f0685ad28c9c82ce67cb; From 7952d40240855932de01bbe81c02bf1416ec91d8 · fixed in f8d14b7bb0063bbbd86c0e4d73edb8cea7b362bc

• Linux Linux

  4.7

• KernelLinux

  From 4.7.0 · fixed in 5.10.271; From 5.11.0 · fixed in 5.15.222; From 5.16.0 · fixed in 6.1.189; From 6.2.0 · fixed in 6.6.158; From 6.7.0 · fixed in 6.12.111; From 6.13.0 · fixed in 6.18.53

References 7