{"cve":"CVE-2026-98923","nvd":{"published":"2026-10-23T13:17:12.957","modified":"2026-10-23T13:17:12.957","status":"Received","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.","cvss_v4":null,"cvss_v3":null,"cwes":[],"references":["https://git.kernel.org/stable/c/0b04af3d88bb7fc69b2d92457890608860e42365","https://git.kernel.org/stable/c/9b583795feb51f8d50203228d001760d1344ef01","https://git.kernel.org/stable/c/b17aa4955e3a694c663ebe99626e4c76ca4f7cfb","https://git.kernel.org/stable/c/bb756b11ad63832ebee58caf9e8f9381eaecff9f","https://git.kernel.org/stable/c/fddc90d4af4550af410f52d11bbf6b5f36443838"],"products":[],"source":"nvd","synced_at":"2026-10-23T16:39:28.036610720+00:00"},"epss":{"cve":"CVE-2026-98923","score":0.00168,"percentile":0.06107,"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."]}