{"id":"CVE-2026-98923","published":"2026-10-23T13:17:12.957","lastModified":"2026-10-23T13:17:12.957","description":"In the Linux kernel, the following vulnerability has been resolved:\n\narm64: io: Reject non-user protection in ioremap_prot()\n\nMapping a stack-top page via /dev/mem with PROT_NONE and then\nreading that process's /proc/<pid>/cmdline triggers a spurious WARN\nin ioremap_prot() through generic_access_phys():\n\n  WARNING: ./arch/arm64/include/asm/io.h:275 at generic_access_phys\n  Call trace:\n    generic_access_phys+0x1c8/0x228 (P)\n    __access_remote_vm+0x2b4/0x398\n    access_remote_vm+0x14/0x30\n    get_mm_cmdline+0xf8/0x2a0\n    proc_pid_cmdline_read+0x68/0x120\n\ngeneric_access_phys() passes the protection derived from the user PTE\nto ioremap_prot(). On arm64, a PROT_NONE mapping is represented by a\npresent-invalid PTE, so pte_present() still returns true and the\nprotection reaches ioremap_prot().\n\nA PROT_NONE mapping does not have PTE_USER, causing the existing\nWARN_ON_ONCE() in ioremap_prot() to fire even though this is a valid\nuser mapping. Execute-only mappings have the same issue and must not\nbe readable through this path either.\n\nioremap_prot() should therefore reject protection values without\nPTE_USER without warning. This makes the access fail cleanly for\nPROT_NONE and execute-only mappings while retaining the existing\nuser-protection contract.","cvssScore":null,"cvssSeverity":null,"cvssVector":null,"cwes":[],"vendors":[],"products":[],"references":[{"url":"https://git.kernel.org/stable/c/0b04af3d88bb7fc69b2d92457890608860e42365","tags":[]},{"url":"https://git.kernel.org/stable/c/9b583795feb51f8d50203228d001760d1344ef01","tags":[]},{"url":"https://git.kernel.org/stable/c/b17aa4955e3a694c663ebe99626e4c76ca4f7cfb","tags":[]},{"url":"https://git.kernel.org/stable/c/bb756b11ad63832ebee58caf9e8f9381eaecff9f","tags":[]},{"url":"https://git.kernel.org/stable/c/fddc90d4af4550af410f52d11bbf6b5f36443838","tags":[]}],"exploitRefs":[],"hasPoc":false,"ai":null}