CVE-2026-68185 Overview
CVE-2026-68185 is a Linux kernel vulnerability affecting the LoongArch architecture. The flaw involves incorrect initialization ordering between jump_label_init() and parse_early_param() during kernel boot. When both CONFIG_MEM_ALLOC_PROFILING=y and CONFIG_MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT=y are enabled, passing the boot parameter sysctl.vm.mem_profiling=0 causes the kernel to fail to boot. The root cause is that early parameter handlers may modify static keys via static_branch_enable/disable() before jump labels are initialized. The patch reorders jump_label_init() to run before parse_early_param(), matching behavior on other architectures.
Critical Impact
A Linux kernel built for LoongArch fails to boot when memory profiling is disabled via early boot parameter, producing a denial-of-service condition on affected systems.
Affected Products
- Linux kernel on LoongArch architecture
- Kernel builds with CONFIG_MEM_ALLOC_PROFILING=y and CONFIG_MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT=y
- Systems using the sysctl.vm.mem_profiling=0 boot parameter
Discovery Timeline
- 2026-08-10 - CVE-2026-68185 published to NVD
- 2026-08-10 - Last updated in NVD database
Technical Details for CVE-2026-68185
Vulnerability Analysis
The vulnerability resides in the LoongArch boot sequence within the Linux kernel. During early initialization, the kernel calls parse_early_param() to process boot command line arguments. Certain early parameter handlers, including the memory allocation profiling handler, invoke static_branch_enable() or static_branch_disable() to toggle static keys. Static keys rely on the jump label infrastructure being initialized via jump_label_init().
On LoongArch, jump_label_init() was invoked after parse_early_param(). When a user passed sysctl.vm.mem_profiling=0 to disable memory profiling that had been compiled in as enabled by default, the handler attempted to manipulate a static key before its underlying jump label table was ready. The result was a boot-time failure preventing the system from starting.
The fix moves jump_label_init() ahead of parse_early_param() in the LoongArch architecture setup path, aligning the ordering with x86, arm64, and other supported architectures.
Root Cause
The root cause is an initialization ordering defect in LoongArch architecture setup code. Static branch APIs assume jump label infrastructure is available, but the LoongArch boot sequence violated this invariant by calling parse_early_param() first.
Attack Vector
This is a local boot-time issue and not a remotely exploitable flaw. Impact is limited to system availability. An operator or automation system supplying the affected kernel command line will encounter a kernel that fails to complete boot.
No exploitation code is applicable. See the upstream fix commits referenced under Kernel Git Commit 881e9f3c and Kernel Git Commit 4b40e590 for the corrective changes.
Detection Methods for CVE-2026-68185
Indicators of Compromise
- LoongArch systems failing to complete kernel boot when sysctl.vm.mem_profiling=0 is present in the kernel command line
- Boot logs showing early panic or hang during parse_early_param() processing on affected kernels
- Systems running LoongArch kernel versions built with memory allocation profiling enabled by default
Detection Strategies
- Inventory LoongArch hosts and identify kernel builds that set CONFIG_MEM_ALLOC_PROFILING and CONFIG_MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT to y
- Audit bootloader configuration files such as GRUB entries for the sysctl.vm.mem_profiling=0 parameter
- Compare running kernel commit hashes against the fixed commits 881e9f3c4e11, 4b40e590efb3, 38b025fcdc45, and ea68d444a658
Monitoring Recommendations
- Track kernel version and configuration drift across LoongArch fleets through configuration management tooling
- Monitor boot success rates and console logs for repeatable early-boot failures after kernel updates
- Alert on unexpected kernel command-line changes applied through provisioning or update pipelines
How to Mitigate CVE-2026-68185
Immediate Actions Required
- Apply the upstream Linux kernel patch that reorders jump_label_init() before parse_early_param() on LoongArch
- Remove the sysctl.vm.mem_profiling=0 boot parameter from LoongArch systems running unpatched kernels
- Rebuild affected kernels without CONFIG_MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT=y if patching is not immediately feasible
Patch Information
The fix has been merged upstream across multiple stable branches. Review the commits at Kernel Git Commit 881e9f3c, Kernel Git Commit 4b40e590, Kernel Git Commit 38b025fc, and Kernel Git Commit ea68d444. Apply the corresponding stable release for your kernel branch.
Workarounds
- Avoid enabling CONFIG_MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT at build time on LoongArch until the patch is applied
- Do not pass sysctl.vm.mem_profiling=0 on the kernel command line for affected builds
- Toggle memory profiling at runtime via sysctl after boot rather than through the early boot parameter
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
