{"id":"CVE-2026-90303","state":"PUBLISHED","title":"ARM: 9485/1: mm: acquire mmap write lock around show_pte() for user faults","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.","publishedAt":"2026-09-17T16:08:26.455Z","updatedAt":"2026-10-19T09:01:21.209Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"6d021b724481fbb908eb29384898deb9f00dfe70","status":"affected","lessThan":"ab14f07952adfe735d86a53518f8cd576dfd5892","versionType":"git"},{"version":"6d021b724481fbb908eb29384898deb9f00dfe70","status":"affected","lessThan":"07e4d5380f2a844ab7a1b440dde350caf561cbb0","versionType":"git"},{"version":"6d021b724481fbb908eb29384898deb9f00dfe70","status":"affected","lessThan":"2a14d7797a49a47bccd1a9327fd69da838dcb0dd","versionType":"git"},{"version":"6d021b724481fbb908eb29384898deb9f00dfe70","status":"affected","lessThan":"63e3c958a602d0896a101a897c2361878c266ca7","versionType":"git"},{"version":"6d021b724481fbb908eb29384898deb9f00dfe70","status":"affected","lessThan":"59bbf86d0ff9373bfa033ca123c1e924f09f1eba","versionType":"git"},{"version":"6d021b724481fbb908eb29384898deb9f00dfe70","status":"affected","lessThan":"c71f9a56520b419e55d173052629f2324deb5549","versionType":"git"},{"version":"6d021b724481fbb908eb29384898deb9f00dfe70","status":"affected","lessThan":"720408d98d9fb3c91a12090436734c8c61f04545","versionType":"git"},{"version":"6d021b724481fbb908eb29384898deb9f00dfe70","status":"affected","lessThan":"1039bffd6ae9c75b42b7d148d6c1106134107b66","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/arm/mm/fault.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.0","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.0","versionType":"semver"},{"version":"5.10.270","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.221","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.188","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.157","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.110","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.52","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.6","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/arm/mm/fault.c"]}],"references":["https://git.kernel.org/stable/c/ab14f07952adfe735d86a53518f8cd576dfd5892","https://git.kernel.org/stable/c/07e4d5380f2a844ab7a1b440dde350caf561cbb0","https://git.kernel.org/stable/c/2a14d7797a49a47bccd1a9327fd69da838dcb0dd","https://git.kernel.org/stable/c/63e3c958a602d0896a101a897c2361878c266ca7","https://git.kernel.org/stable/c/59bbf86d0ff9373bfa033ca123c1e924f09f1eba","https://git.kernel.org/stable/c/c71f9a56520b419e55d173052629f2324deb5549","https://git.kernel.org/stable/c/720408d98d9fb3c91a12090436734c8c61f04545","https://git.kernel.org/stable/c/1039bffd6ae9c75b42b7d148d6c1106134107b66"],"weaknesses":[],"ingestedAt":"2026-10-29T20:13:34.582Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/90xxx/CVE-2026-90303.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-90303","state":"PUBLISHED","datePublished":"2026-09-17T16:08:26.455Z","dateUpdated":"2026-10-19T09:01:21.209Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-11T19:38:34.799Z"},"containers":{"cna":{"title":"ARM: 9485/1: mm: acquire mmap write lock around show_pte() for user faults","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"6d021b724481fbb908eb29384898deb9f00dfe70","status":"affected","lessThan":"ab14f07952adfe735d86a53518f8cd576dfd5892","versionType":"git"},{"version":"6d021b724481fbb908eb29384898deb9f00dfe70","status":"affected","lessThan":"07e4d5380f2a844ab7a1b440dde350caf561cbb0","versionType":"git"},{"version":"6d021b724481fbb908eb29384898deb9f00dfe70","status":"affected","lessThan":"2a14d7797a49a47bccd1a9327fd69da838dcb0dd","versionType":"git"},{"version":"6d021b724481fbb908eb29384898deb9f00dfe70","status":"affected","lessThan":"63e3c958a602d0896a101a897c2361878c266ca7","versionType":"git"},{"version":"6d021b724481fbb908eb29384898deb9f00dfe70","status":"affected","lessThan":"59bbf86d0ff9373bfa033ca123c1e924f09f1eba","versionType":"git"},{"version":"6d021b724481fbb908eb29384898deb9f00dfe70","status":"affected","lessThan":"c71f9a56520b419e55d173052629f2324deb5549","versionType":"git"},{"version":"6d021b724481fbb908eb29384898deb9f00dfe70","status":"affected","lessThan":"720408d98d9fb3c91a12090436734c8c61f04545","versionType":"git"},{"version":"6d021b724481fbb908eb29384898deb9f00dfe70","status":"affected","lessThan":"1039bffd6ae9c75b42b7d148d6c1106134107b66","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/arm/mm/fault.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.0","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.0","versionType":"semver"},{"version":"5.10.270","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.221","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.188","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.157","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.110","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.52","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.6","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/arm/mm/fault.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/ab14f07952adfe735d86a53518f8cd576dfd5892"},{"url":"https://git.kernel.org/stable/c/07e4d5380f2a844ab7a1b440dde350caf561cbb0"},{"url":"https://git.kernel.org/stable/c/2a14d7797a49a47bccd1a9327fd69da838dcb0dd"},{"url":"https://git.kernel.org/stable/c/63e3c958a602d0896a101a897c2361878c266ca7"},{"url":"https://git.kernel.org/stable/c/59bbf86d0ff9373bfa033ca123c1e924f09f1eba"},{"url":"https://git.kernel.org/stable/c/c71f9a56520b419e55d173052629f2324deb5549"},{"url":"https://git.kernel.org/stable/c/720408d98d9fb3c91a12090436734c8c61f04545"},{"url":"https://git.kernel.org/stable/c/1039bffd6ae9c75b42b7d148d6c1106134107b66"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-19T09:01:21.209Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.0","versionEndExcluding":"5.10.270"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.0","versionEndExcluding":"5.15.221"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.0","versionEndExcluding":"6.1.188"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.0","versionEndExcluding":"6.6.157"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.0","versionEndExcluding":"6.12.110"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.0","versionEndExcluding":"6.18.52"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.0","versionEndExcluding":"7.2.6"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.0","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}