CVE-2025-37760 mm/vma: add give_up_on_oom option on modify/merge, use in uffd release
A flaw in the Linux kernel's memory management allows an attacker to trigger a null pointer dereference via userfaultfd, causing a system crash.
- 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-2025-37760?
CVE-2025-37760 is a medium-severity vulnerability in Linux kernel, published on 1 May 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:
mm/vma: add give_up_on_oom option on modify/merge, use in uffd release
Currently, if a VMA merge fails due to an OOM condition arising on commit merge or a failure to duplicate anon_vma's, we report this so the caller can handle it.
However there are cases where the caller is only ostensibly trying a merge, and doesn't mind if it fails due to this condition.
Since we do not want to introduce an implicit assumption that we only actually modify VMAs after OOM conditions might arise, add a 'give up on oom' option and make an explicit contract that, should this flag be set, we absolutely will not modify any VMAs should OOM arise and just bail out.
Since it'd be very unusual for a user to try to vma_modify() with this flag set but be specifying a range within a VMA which ends up being split (which can fail due to rlimit issues, not only OOM), we add a debug warning for this condition.
The motivating reason for this is uffd release - syzkaller (and Pedro Falcato's VERY astute analysis) found a way in which an injected fault on allocation, triggering an OOM condition on commit merge, would result in uffd code becoming confused and treating an error value as if it were a VMA pointer.
To avoid this, we make use of this new VMG flag to ensure that this never occurs, utilising the fact that, should we be clearing entire VMAs, we do not wish an OOM event to be reported to us.
Many thanks to Pedro Falcato for his excellent analysis and Jann Horn for his insightful and intelligent analysis of the situation, both of whom were instrumental in this fix.
Which versions are affected by CVE-2025-37760?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2025-37760?
Apply the vendor's patch.
Is CVE-2025-37760 being exploited?
There is no known exploitation of CVE-2025-37760 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2025-37760, DEBIAN-CVE-2025-37760, GHSA-p4vj-hhfc-5j8x, UBUNTU-CVE-2025-37760.