{"id":"CVE-2026-98923","state":"PUBLISHED","title":"arm64: io: Reject non-user protection in ioremap_prot()","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.","publishedAt":"2026-10-23T12:03:28.027Z","updatedAt":"2026-10-23T12:05:45.179Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"64858b76ec67c5fc40fef8ec1841fecb78c1ebde","status":"affected","lessThan":"fddc90d4af4550af410f52d11bbf6b5f36443838","versionType":"git"},{"version":"eeecafce5afffb4da703666ebefbd4d6e2a5abf6","status":"affected","lessThan":"0b04af3d88bb7fc69b2d92457890608860e42365","versionType":"git"},{"version":"3d64dcc0799c2d6921ba027716b7be721eb19fa8","status":"affected","lessThan":"b17aa4955e3a694c663ebe99626e4c76ca4f7cfb","versionType":"git"},{"version":"8f098037139b294050053123ab2bc0f819d08932","status":"affected","lessThan":"9b583795feb51f8d50203228d001760d1344ef01","versionType":"git"},{"version":"8f098037139b294050053123ab2bc0f819d08932","status":"affected","lessThan":"bb756b11ad63832ebee58caf9e8f9381eaecff9f","versionType":"git"},{"version":"d1ad8fe7f72d73e1617bac79f2ec7a3bedf47e2a","status":"affected","versionType":"git"},{"version":"6.6.143","status":"affected","lessThan":"6.6.158","versionType":"semver"},{"version":"6.12.93","status":"affected","lessThan":"6.12.112","versionType":"semver"},{"version":"6.18.17","status":"affected","lessThan":"6.18.55","versionType":"semver"},{"version":"6.19.7","status":"affected","lessThan":"6.20","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/arm64/include/asm/io.h"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"7.0","status":"affected"},{"version":"0","status":"unaffected","lessThan":"7.0","versionType":"semver"},{"version":"6.6.158","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.112","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.55","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.9","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/arm64/include/asm/io.h"]}],"references":["https://git.kernel.org/stable/c/fddc90d4af4550af410f52d11bbf6b5f36443838","https://git.kernel.org/stable/c/0b04af3d88bb7fc69b2d92457890608860e42365","https://git.kernel.org/stable/c/b17aa4955e3a694c663ebe99626e4c76ca4f7cfb","https://git.kernel.org/stable/c/9b583795feb51f8d50203228d001760d1344ef01","https://git.kernel.org/stable/c/bb756b11ad63832ebee58caf9e8f9381eaecff9f"],"weaknesses":[],"ingestedAt":"2026-10-29T20:13:43.249Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/98xxx/CVE-2026-98923.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-98923","state":"PUBLISHED","datePublished":"2026-10-23T12:03:28.027Z","dateUpdated":"2026-10-23T12:05:45.179Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-25T10:25:14.380Z"},"containers":{"cna":{"title":"arm64: io: Reject non-user protection in ioremap_prot()","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"64858b76ec67c5fc40fef8ec1841fecb78c1ebde","status":"affected","lessThan":"fddc90d4af4550af410f52d11bbf6b5f36443838","versionType":"git"},{"version":"eeecafce5afffb4da703666ebefbd4d6e2a5abf6","status":"affected","lessThan":"0b04af3d88bb7fc69b2d92457890608860e42365","versionType":"git"},{"version":"3d64dcc0799c2d6921ba027716b7be721eb19fa8","status":"affected","lessThan":"b17aa4955e3a694c663ebe99626e4c76ca4f7cfb","versionType":"git"},{"version":"8f098037139b294050053123ab2bc0f819d08932","status":"affected","lessThan":"9b583795feb51f8d50203228d001760d1344ef01","versionType":"git"},{"version":"8f098037139b294050053123ab2bc0f819d08932","status":"affected","lessThan":"bb756b11ad63832ebee58caf9e8f9381eaecff9f","versionType":"git"},{"version":"d1ad8fe7f72d73e1617bac79f2ec7a3bedf47e2a","status":"affected","versionType":"git"},{"version":"6.6.143","status":"affected","lessThan":"6.6.158","versionType":"semver"},{"version":"6.12.93","status":"affected","lessThan":"6.12.112","versionType":"semver"},{"version":"6.18.17","status":"affected","lessThan":"6.18.55","versionType":"semver"},{"version":"6.19.7","status":"affected","lessThan":"6.20","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/arm64/include/asm/io.h"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"7.0","status":"affected"},{"version":"0","status":"unaffected","lessThan":"7.0","versionType":"semver"},{"version":"6.6.158","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.112","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.55","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.9","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/arm64/include/asm/io.h"]}],"references":[{"url":"https://git.kernel.org/stable/c/fddc90d4af4550af410f52d11bbf6b5f36443838"},{"url":"https://git.kernel.org/stable/c/0b04af3d88bb7fc69b2d92457890608860e42365"},{"url":"https://git.kernel.org/stable/c/b17aa4955e3a694c663ebe99626e4c76ca4f7cfb"},{"url":"https://git.kernel.org/stable/c/9b583795feb51f8d50203228d001760d1344ef01"},{"url":"https://git.kernel.org/stable/c/bb756b11ad63832ebee58caf9e8f9381eaecff9f"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-23T12:05:45.179Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.6.143","versionEndExcluding":"6.6.158"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12.93","versionEndExcluding":"6.12.112"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.18.17","versionEndExcluding":"6.18.55"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.0","versionEndExcluding":"7.2.9"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.0","versionEndExcluding":"7.3"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.19.7"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}