CVE-2025-37885 KVM: x86: Reset IRTE to host control if *new* route isn't postable
A use-after-free in Linux KVM allows attackers to execute code or escalate privileges via incorrect interrupt delivery when GSI routes change.
- 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-2025-37885?
CVE-2025-37885 is a high-severity use after free vulnerability in Debian Debian Linux, published on 9 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:
KVM: x86: Reset IRTE to host control if *new* route isn't postable
Restore an IRTE back to host control (remapped or posted MSI mode) if the *new* GSI route prevents posting the IRQ directly to a vCPU, regardless of the GSI routing type. Updating the IRTE if and only if the new GSI is an MSI results in KVM leaving an IRTE posting to a vCPU.
The dangling IRTE can result in interrupts being incorrectly delivered to the guest, and in the worst case scenario can result in use-after-free, e.g. if the VM is torn down, but the underlying host IRQ isn't freed.
Weakness: CWE-416
Which versions are affected by CVE-2025-37885?
It affects 2 products.
Products include Debian Debian Linux, Linux kernel.
How do I fix CVE-2025-37885?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2025-37885 being exploited?
There is no known exploitation of CVE-2025-37885 in the wild and no public exploit code.
Other vulnerabilities in Debian Debian Linux
Sources
Also known as BELL-CVE-2025-37885, DEBIAN-CVE-2025-37885, GHSA-jrv2-7qh6-cgcr, ROOT-OS-DEBIAN-12-CVE-2025-37885, ROOT-OS-UBUNTU-2204-CVE-2025-37885, ROOT-OS-UBUNTU-2404-CVE-2025-37885 and 1 more.