CVE Catalog

CVE-2026-98923

Unknown
Published: Translated: NVD NIST

Summary

In the Linux kernel on arm64, ioremap_prot() did not reject mappings lacking the PTE_USER flag, causing a spurious WARN when accessing PROT_NONE or execute-only pages via /dev/mem and /proc/<pid>/cmdline. The fix makes such protection values fail cleanly without warning.

Risk Assessment

A local user can trigger spurious kernel warnings and potentially destabilize the system by accessing mappings without user protection. On systems configured with panic-on-warn this may lead to denial of service.

Recommendation

Update the Linux kernel to a version containing the arm64 ioremap_prot() fix. Until patched, consider disabling panic-on-warn on production systems.

Other vulnerabilities in Linux kernel

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Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: arm64: io: Reject non-user protection in ioremap_prot() Mapping a stack-top page via /dev/mem with PROT_NONE and then reading that process's /proc/<pid>/cmdline triggers a spurious WARN in ioremap_prot() through generic_access_phys(): WARNING: ./arch/arm64/include/asm/io.h:275 at generic_access_phys Call trace: generic_access_phys+0x1c8/0x228 (P) __access_remote_vm+0x2b4/0x398 access_remote_vm+0x14/0x30 get_mm_cmdline+0xf8/0x2a0 proc_pid_cmdline_read+0x68/0x120 generic_access_phys() passes the protection derived from the user PTE to ioremap_prot(). On arm64, a PROT_NONE mapping is represented by a present-invalid PTE, so pte_present() still returns true and the protection reaches ioremap_prot(). A PROT_NONE mapping does not have PTE_USER, causing the existing WARN_ON_ONCE() in ioremap_prot() to fire even though this is a valid user mapping. Execute-only mappings have the same issue and must not be readable through this path either. ioremap_prot() should therefore reject protection values without PTE_USER without warning. This makes the access fail cleanly for PROT_NONE and execute-only mappings while retaining the existing user-protection contract.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS