{"id":"CVE-2026-90303","title":"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_…","summary":"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_…","severity":"medium","vendor":"Linux","product":"Linux","affected":["Linux >= 6d021b724481fbb908eb29384898deb9f00dfe70 < ab14f07952adfe735d86a53518f8cd576dfd5892","Linux >= 6d021b724481fbb908eb29384898deb9f00dfe70 < 07e4d5380f2a844ab7a1b440dde350caf561cbb0","Linux >= 6d021b724481fbb908eb29384898deb9f00dfe70 < 2a14d7797a49a47bccd1a9327fd69da838dcb0dd","Linux >= 6d021b724481fbb908eb29384898deb9f00dfe70 < 63e3c958a602d0896a101a897c2361878c266ca7","Linux >= 6d021b724481fbb908eb29384898deb9f00dfe70 < 59bbf86d0ff9373bfa033ca123c1e924f09f1eba","Linux >= 6d021b724481fbb908eb29384898deb9f00dfe70 < c71f9a56520b419e55d173052629f2324deb5549","Linux >= 6d021b724481fbb908eb29384898deb9f00dfe70 < 720408d98d9fb3c91a12090436734c8c61f04545","Linux >= 6d021b724481fbb908eb29384898deb9f00dfe70 < 1039bffd6ae9c75b42b7d148d6c1106134107b66","Linux 4.0"],"published":"2026-09-17","updated":"2026-09-17","sourceUpdated":"2026-09-17T17:17:27.887","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-90303","references":[{"url":"https://git.kernel.org/stable/c/07e4d5380f2a844ab7a1b440dde350caf561cbb0","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/1039bffd6ae9c75b42b7d148d6c1106134107b66","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/2a14d7797a49a47bccd1a9327fd69da838dcb0dd","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/59bbf86d0ff9373bfa033ca123c1e924f09f1eba","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/63e3c958a602d0896a101a897c2361878c266ca7","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/720408d98d9fb3c91a12090436734c8c61f04545","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/ab14f07952adfe735d86a53518f8cd576dfd5892","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/c71f9a56520b419e55d173052629f2324deb5549","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-90303.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-90303"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2536673"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-90303"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-90303"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-90303.mbox"},{"url":"https://kernelcve.org/list/?q=CVE-2026-90303"}],"tags":["nvd","cve.org","csaf","vex","red-hat"],"ingestedAt":"2026-09-17T16:21:47.828Z","epss":0.0022,"epssPercentile":0.12394,"cvss":4.7,"cvssVector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H","cvssSource":"vendor","cwe":["CWE-416"],"slug":"CVE-2026-90303","body":"## Overview\n\nIn 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, … · updated 2026-10-23 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-90303.json)","depth":"sunlit","depthScore":26,"depthScoreParts":{"impact":25.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":228212,"id":"CVE-2026-90303","ts":1792758194519,"field":"cvss","old":null,"new":"4.7"},{"seq":228211,"id":"CVE-2026-90303","ts":1792758194519,"field":"severity","old":"none","new":"medium"}]}