CVE-2025-38071 x86/mm: Check return value from memblock_phys_alloc_range()
A missing return value check in the Linux kernel x86 memory management code can cause a system crash when contiguous memory is scarce.
- 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-2025-38071?
CVE-2025-38071 is a medium-severity vulnerability in Debian Debian Linux, published on 18 Jun 2025. 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:
x86/mm: Check return value from memblock_phys_alloc_range()
At least with CONFIG_PHYSICAL_START=0x100000, if there is < 4 MiB of contiguous free memory available at this point, the kernel will crash and burn because memblock_phys_alloc_range() returns 0 on failure, which leads memblock_phys_free() to throw the first 4 MiB of physical memory to the wolves.
At a minimum it should fail gracefully with a meaningful diagnostic, but in fact everything seems to work fine without the weird reserve allocation.
Which versions are affected by CVE-2025-38071?
It affects 2 products.
Products include Debian Debian Linux, Linux kernel.
How do I fix CVE-2025-38071?
Apply the vendor's patch.
Is CVE-2025-38071 being exploited?
There is no known exploitation of CVE-2025-38071 in the wild and no public exploit code.
Other vulnerabilities in Debian Debian Linux
Sources
Also known as AZL-63983, AZL-72713, BELL-CVE-2025-38071, DEBIAN-CVE-2025-38071, GHSA-fcf5-p95m-fc28, ROOT-OS-DEBIAN-11-CVE-2025-38071 and 4 more.