Executive brief
A vulnerability was identified in the Linux kernel's memory management subsystem, specifically within the DAMON LRU Sort module which helps optimize system memory usage. Under certain conditions where the system runs out of memory during initialization, the kernel could attempt to use a non-existent data structure, leading to a system crash. This could result in a denial-of-service, impacting the availability of the affected server or device.
Technical details
A NULL pointer dereference exists in mm/damon/lru_sort.c within the Linux kernel. The DAMON_LRU_SORT module allocates a 'damon_ctx' object during initialization; however, the 'damon_lru_sort_enabled_store()' function failed to verify if this allocation was successful. If the allocation fails (e.g., due to memory exhaustion), subsequent calls to 'damon_commit_ctx()' dereference the NULL 'ctx' pointer. This is a local vulnerability that can be triggered when an administrator or automated process attempts to enable LRU sorting on a system where the initial context allocation failed. Patches have been released for various stable kernel branches including 6.18.x and 7.0.x.
Affected products
- Linux Linux Kernel 6.18 to 6.18.36, 7.0 to 7.0.13
Timeline
- 2026-07-01: advisory
- 2026-07-01: disclosed