{"id":"CVE-2026-90303","summary":"ARM: 9485/1: mm: acquire mmap write lock around show_pte() for user faults","details":"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 \u003c TASK_SIZE). This is because\nthe lock of tsk-\u003emm 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.","modified":"2026-09-19T03:47:28.902339726Z","published":"2026-09-17T16:08:26.455Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90303.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/07e4d5380f2a844ab7a1b440dde350caf561cbb0"},{"type":"WEB","url":"https://git.kernel.org/stable/c/1039bffd6ae9c75b42b7d148d6c1106134107b66"},{"type":"WEB","url":"https://git.kernel.org/stable/c/2a14d7797a49a47bccd1a9327fd69da838dcb0dd"},{"type":"WEB","url":"https://git.kernel.org/stable/c/59bbf86d0ff9373bfa033ca123c1e924f09f1eba"},{"type":"WEB","url":"https://git.kernel.org/stable/c/63e3c958a602d0896a101a897c2361878c266ca7"},{"type":"WEB","url":"https://git.kernel.org/stable/c/720408d98d9fb3c91a12090436734c8c61f04545"},{"type":"WEB","url":"https://git.kernel.org/stable/c/ab14f07952adfe735d86a53518f8cd576dfd5892"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c71f9a56520b419e55d173052629f2324deb5549"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90303.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-90303"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"6d021b724481fbb908eb29384898deb9f00dfe70"},{"fixed":"ab14f07952adfe735d86a53518f8cd576dfd5892"},{"fixed":"07e4d5380f2a844ab7a1b440dde350caf561cbb0"},{"fixed":"2a14d7797a49a47bccd1a9327fd69da838dcb0dd"},{"fixed":"63e3c958a602d0896a101a897c2361878c266ca7"},{"fixed":"59bbf86d0ff9373bfa033ca123c1e924f09f1eba"},{"fixed":"c71f9a56520b419e55d173052629f2324deb5549"},{"fixed":"720408d98d9fb3c91a12090436734c8c61f04545"},{"fixed":"1039bffd6ae9c75b42b7d148d6c1106134107b66"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-90303.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.0.0"},{"fixed":"5.10.270"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.221"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.188"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.157"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.110"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.52"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.2.6"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-90303.json"}}],"schema_version":"1.9.0"}