CVE-2024-35996 cpu: Re-enable CPU mitigations by default for !X86 architectures
Non-x86 Linux kernels may disable CPU mitigations by default, allowing attackers to bypass security protections if specific build configurations are used.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2024-35996?
CVE-2024-35996 is a medium-severity vulnerability in Debian Debian Linux, published on 20 May 2024. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
cpu: Re-enable CPU mitigations by default for !X86 architectures
Rename x86's to CPU_MITIGATIONS, define it in generic code, and force it on for all architectures exception x86. A recent commit to turn mitigations off by default if SPECULATION_MITIGATIONS=n kinda sorta missed that "cpu_mitigations" is completely generic, whereas SPECULATION_MITIGATIONS is x86-specific.
Rename x86's SPECULATIVE_MITIGATIONS instead of keeping both and have it select CPU_MITIGATIONS, as having two configs for the same thing is unnecessary and confusing. This will also allow x86 to use the knob to manage mitigations that aren't strictly related to speculative execution.
Use another Kconfig to communicate to common code that CPU_MITIGATIONS is already defined instead of having x86's menu depend on the common CPU_MITIGATIONS. This allows keeping a single point of contact for all of x86's mitigations, and it's not clear that other architectures *want* to allow disabling mitigations at compile-time.
Which versions are affected by CVE-2024-35996?
It affects 2 products.
Products include Debian Debian Linux, Linux kernel.
How do I fix CVE-2024-35996?
Apply the vendor's patch.
Is CVE-2024-35996 being exploited?
There is no known exploitation of CVE-2024-35996 in the wild and no public exploit code.
Other vulnerabilities in Debian Debian Linux
Sources
Also known as BELL-CVE-2024-35996, DEBIAN-CVE-2024-35996, GHSA-jxch-924p-fpfw, UBUNTU-CVE-2024-35996.