CVE-2025-39763 ACPI: APEI: send SIGBUS to current task if synchronous memory error not recovered
A local attacker can trigger a system reboot or hard lockup by causing unhandled synchronous memory errors, leading to denial of service.
- 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-2025-39763?
CVE-2025-39763 is a medium-severity denial of service vulnerability in Linux kernel, published on 11 Sep 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:
ACPI: APEI: send SIGBUS to current task if synchronous memory error not recovered
If a synchronous error is detected as a result of user-space process triggering a 2-bit uncorrected error, the CPU will take a synchronous error exception such as Synchronous External Abort (SEA) on Arm64. The kernel will queue a memory_failure() work which poisons the related page, unmaps the page, and then sends a SIGBUS to the process, so that a system wide panic can be avoided.
However, no memory_failure() work will be queued when abnormal synchronous errors occur. These errors can include situations like invalid PA, unexpected severity, no memory failure config support, invalid GUID section, etc. In such a case, the user-space process will trigger SEA again. This loop can potentially exceed the platform firmware threshold or even trigger a kernel hard lockup, leading to a system reboot.
Fix it by performing a force kill if no memory_failure() work is queued for synchronous errors.
[ rjw: Changelog edits ]
Which versions are affected by CVE-2025-39763?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2025-39763?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2025-39763 being exploited?
There is no known exploitation of CVE-2025-39763 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-67217, AZL-70825, BELL-CVE-2025-39763, DEBIAN-CVE-2025-39763, GHSA-g7f2-49vp-j5f7, ROOT-OS-DEBIAN-11-CVE-2025-39763 and 4 more.