Medium [CVE-2026-68435] Fix address space mismatch in kexec command line lookup
This medium-severity Red Hat Linux advisory covers CVE-2026-68435 affecting Red Hat Enterprise Linux 10, Red Hat Enterprise Linux for NVIDIA 26, Red Hat package: kernel.
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Summary
In the Linux kernel, the following vulnerability has been resolved: LoongArch: Fix address space mismatch in kexec command line lookup When searching the loaded segments for the "kexec" command line marker, the kexec_load(2) path (file_mode == 0) passes the user-space segment buffer straight to strncmp() through a bogus (char __user *) cast.
This dereferences a user pointer in kernel context, which is wrong and is flagged by sparse: arch/loongarch/kernel/machine_kexec.c:84:51: sparse: incorrect type in argument 2 (different address spaces) @@ expected char const * @@ got char [noderef] __user * Here copy the marker-sized prefix of each segment into a small on-stack buffer with copy_from_user() before comparing, and skip segments that fault.
The subsequent copy_from_user() that stages the full command line into the safe area is left unchanged. A local attacker could exploit this by using the `kexec_load` system call, which incorrectly passes a user-space segment buffer to a kernel function without proper validation.
This improper handling leads to dereferencing a user pointer in kernel context, potentially resulting in a denial of service or information disclosure. Red Hat severity: Moderate — CVSS 5.5 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H).
Weakness: CWE-822. Affected Red Hat products: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux for NVIDIA 26.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · medium-confidence parse· fetched 1 hour ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · medium-confidence parse· fetched 1 hour ago·verify at source
Mitigation
The source record does not include mitigation steps. That is not a statement that no fix exists — read the vendor advisory below for the authoritative guidance.
Official advisory · medium-confidence parse· fetched 1 hour ago·verify at source
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