CVE-2024-49858 efistub/tpm: Use ACPI reclaim memory for event log to avoid corruption
A memory corruption issue in the Linux kernel TPM event log handling can cause a kernel crash during kexec operations.
- 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-2024-49858?
CVE-2024-49858 is a medium-severity memory corruption vulnerability in Linux kernel, published on 21 Oct 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:
efistub/tpm: Use ACPI reclaim memory for event log to avoid corruption
The TPM event log table is a Linux specific construct, where the data produced by the GetEventLog() boot service is cached in memory, and passed on to the OS using an EFI configuration table.
The use of EFI_LOADER_DATA here results in the region being left unreserved in the E820 memory map constructed by the EFI stub, and this is the memory description that is passed on to the incoming kernel by kexec, which is therefore unaware that the region should be reserved.
Even though the utility of the TPM2 event log after a kexec is questionable, any corruption might send the parsing code off into the weeds and crash the kernel. So let's use EFI_ACPI_RECLAIM_MEMORY instead, which is always treated as reserved by the E820 conversion logic.
Which versions are affected by CVE-2024-49858?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2024-49858?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2024-49858 being exploited?
There is no known exploitation of CVE-2024-49858 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-50773, AZL-50957, BELL-CVE-2024-49858, DEBIAN-CVE-2024-49858, GHSA-2pcf-5mqc-gcgr, UBUNTU-CVE-2024-49858.