{"cve":"CVE-2026-90303","nvd":{"published":"2026-09-17T17:17:27.887","modified":"2026-10-19T09:19:24.310","status":"Received","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.","cvss_v4":null,"cvss_v3":null,"cwes":[],"references":["https://git.kernel.org/stable/c/07e4d5380f2a844ab7a1b440dde350caf561cbb0","https://git.kernel.org/stable/c/1039bffd6ae9c75b42b7d148d6c1106134107b66","https://git.kernel.org/stable/c/2a14d7797a49a47bccd1a9327fd69da838dcb0dd","https://git.kernel.org/stable/c/59bbf86d0ff9373bfa033ca123c1e924f09f1eba","https://git.kernel.org/stable/c/63e3c958a602d0896a101a897c2361878c266ca7"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:55:23.253742848+00:00"},"epss":{"cve":"CVE-2026-90303","score":0.0022,"percentile":0.12349,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}