{"id":"CVE-2026-90303","published":"2026-09-17T17:17:27.887","lastModified":"2026-09-17T17:17:27.887","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nARM: 9485/1: mm: acquire mmap write lock around show_pte() for user faults\n\nWhen CONFIG_DEBUG_USER=y, and cmdline \"user_debug=31\" is set,\na user fault may trigger show_pte() without any lock.\nIf another thread in the same process concurrently calls munmap(),\nthe page table pages may be freed while show_pte() is still traversing\nthem, causing a use-after-free in show_pte().\n\nIf CONFIG_ARM_LPAE=y, this may cause a kernel panic if the pages table\nof PMD are freed when show_pte() is running.\n\nAcquire mmap_write_lock() around show_pte() for user faults to fix the\ncontention.\n\nFor user faults, additionally restrict that show_pte() is called only\nwhen the addr is a user-space address (addr < TASK_SIZE). This is because\nthe lock of tsk->mm only protects the virtual memory of user address space,\nfurthermore, dumping the page tables of a kernel-space address for user\nfaults is unnecessary and may have security implications.\n\nKeep everything unchanged for kernel faults, because the kernel is\nalready in the \"oops\" state, acquiring a lock may risk a deadlock.","cvssScore":null,"cvssSeverity":null,"cvssVector":null,"cwes":[],"vendors":[],"products":[],"references":[{"url":"https://git.kernel.org/stable/c/07e4d5380f2a844ab7a1b440dde350caf561cbb0","tags":[]},{"url":"https://git.kernel.org/stable/c/1039bffd6ae9c75b42b7d148d6c1106134107b66","tags":[]},{"url":"https://git.kernel.org/stable/c/2a14d7797a49a47bccd1a9327fd69da838dcb0dd","tags":[]},{"url":"https://git.kernel.org/stable/c/59bbf86d0ff9373bfa033ca123c1e924f09f1eba","tags":[]},{"url":"https://git.kernel.org/stable/c/63e3c958a602d0896a101a897c2361878c266ca7","tags":[]},{"url":"https://git.kernel.org/stable/c/720408d98d9fb3c91a12090436734c8c61f04545","tags":[]},{"url":"https://git.kernel.org/stable/c/ab14f07952adfe735d86a53518f8cd576dfd5892","tags":[]},{"url":"https://git.kernel.org/stable/c/c71f9a56520b419e55d173052629f2324deb5549","tags":[]}],"exploitRefs":[],"hasPoc":false,"ai":null}