Bug 2514452 (CVE-2026-68435)

Summary: CVE-2026-68435 kernel: LoongArch: Fix address space mismatch in kexec command line lookup
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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Doc Text:
A flaw was found in the Linux kernel, specifically within the LoongArch architecture's `kexec` command line lookup functionality. 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.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Description OSIDB Bzimport 2026-08-12 00:22:15 UTC 
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.
Comment 1 gkamathe 2026-08-12 05:10:30 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026081255-CVE-2026-68435-6d41@gregkh/T