CVE-2025-39763: ACPI: APEI: send SIGBUS to current task if synchronous memory error not recovered

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-09-11 · updated 2026-10-19

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 ]

Affected products

Linux kernel: before 6.6.103; from 6.7 before 6.12.43; from 6.13 before 6.15.11; from 6.16 before 6.16.2 — fixed in 6.12.43, 6.15.11, 6.16.2, 6.6.103

How to fix

Upgrade to a fixed version: Linux kernel 6.12.43, 6.15.11, 6.16.2, 6.6.103. Check the vendor advisory for mitigations.

References

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