CVE-2024-50112

What it actually does

The kernel permitted Linear Address Masking (LAM) to remain enabled in production builds without Linear Address Space Separation (LASS), leaving a transient-execution weakness (SLAM) that could be reached via address masking.

Why it matters to the business

No operational impact exists today because no shipping processors implement LAM; the change simply prevents a future exposure once hardware arrives and reduces downstream kernel rebuild or distribution risk.

How an attack unfolds

An attacker would require LAM-capable silicon, disable or bypass LASS, then use transient execution to observe masked address bits as described in the SLAM paper; no such hardware or public exploit exists.

How to fix it

Update the Linux kernel source to commit 60a5ba560f296ad8da153f6ad3f70030bfa3958f or later; rebuild and deploy the resulting kernel image. Do not enable LAM via CONFIG_X86_LAM unless the build is strictly for compile testing or all CPU mitigations are deliberately disabled.

How to confirm the fix worked

Inspect kernel configuration or source for the LAM disable logic around ADDRESS_MASKING; confirm that LAM is only compiled when CONFIG_COMPILE_TEST=y or CPU_MITIGATIONS=n; boot the updated kernel on available hardware and verify /proc/cpuinfo or dmesg shows LAM remains off.

Typical attack path

1. Obtain or emulate LAM-enabled x86 hardware
2. Ensure LASS is not active
3. Trigger speculative execution that leaks masked linear addresses
4. Recover sensitive data from the transient window

How to detect it

No exploitation has been observed; search kernel build logs and configuration files for any custom enablement of LAM or disabling of CPU mitigations that would have activated the vulnerable path.

What your security team should do

• Apply the referenced commit in all kernel build pipelines within the next maintenance window
• Add a build-time check that rejects LAM enablement in production configurations
• Monitor upstream LASS support patches and re-evaluate LAM once LASS is merged