Executive brief
A vulnerability in the Linux kernel's PowerPC architecture support could allow a local user to cause a system crash. The issue occurs when the system fails to properly handle memory allocation failures during the processing of processor thread groups. This could lead to a denial-of-service condition, impacting the availability of affected servers or workstations.
Technical details
A NULL pointer dereference vulnerability exists in arch/powerpc/kernel/smp.c within the parse_thread_groups() function. The vulnerability is caused by a missing check for the return value of kcalloc() when allocating memory for the thread_group_array. If memory allocation fails, the resulting NULL pointer is passed to of_property_read_u32_array(), leading to a kernel panic. This issue specifically affects PowerPC systems parsing 'ibm,thread-groups' device tree properties. An attacker with local access could potentially trigger this condition to cause a Denial of Service (DoS). Patches have been released across multiple stable kernel branches to ensure the kcalloc() return value is validated before use.
Affected products
- Linux Linux Kernel 5.11 to 5.15.202, 5.16 to 6.1.165, 6.2 to 6.6.128, 6.7 to 6.12.75, 6.13 to 6.18.16, 6.19 to 6.19.6
Timeline
- 2026-05-06: advisory: CVE-2026-43148 published by kernel.org
- 2026-05-13: other: NIST analysis and CVSS score added
References
- https://git.kernel.org/stable/c/1de31dba19c3cd0c1caf388a286b46df638f0b91
- https://git.kernel.org/stable/c/33c1c6d8a28a2761ac74b0380b2563cf546c2a3a
- https://git.kernel.org/stable/c/8b221db0b7d24675e465e98d9326d298025a4e8d
- https://git.kernel.org/stable/c/9b85c8f624b0f8cf9b932f5a65dacd56a1f47a72
- https://git.kernel.org/stable/c/9d0ca11258e7b452653d04310addfec1753de1a2
- https://git.kernel.org/stable/c/b265e53d9adfbb5751713185843f7188aa9dd066
- https://git.kernel.org/stable/c/ca46d2092f307385a7acfb42632056570d6dbbbc