CVE-2025-37949 Affecting kernel-uek-core package, versions <0:5.15.0-310.184.5.2.el8uek


Severity

Recommended
high

Based on Oracle Linux security rating.

Threat Intelligence

EPSS
0.05% (16th percentile)

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  • Snyk IDSNYK-ORACLE8-KERNELUEKCORE-10767701
  • published17 Jul 2025
  • disclosed20 May 2025

Introduced: 20 May 2025

CVE-2025-37949  (opens in a new tab)

How to fix?

Upgrade Oracle:8 kernel-uek-core to version 0:5.15.0-310.184.5.2.el8uek or higher.
This issue was patched in ELSA-2025-20470.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-uek-core package and not the kernel-uek-core package as distributed by Oracle. See How to fix? for Oracle:8 relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

xenbus: Use kref to track req lifetime

Marek reported seeing a NULL pointer fault in the xenbus_thread callstack: BUG: kernel NULL pointer dereference, address: 0000000000000000 RIP: e030:__wake_up_common+0x4c/0x180 Call Trace: <TASK> __wake_up_common_lock+0x82/0xd0 process_msg+0x18e/0x2f0 xenbus_thread+0x165/0x1c0

process_msg+0x18e is req->cb(req). req->cb is set to xs_wake_up(), a thin wrapper around wake_up(), or xenbus_dev_queue_reply(). It seems like it was xs_wake_up() in this case.

It seems like req may have woken up the xs_wait_for_reply(), which kfree()ed the req. When xenbus_thread resumes, it faults on the zero-ed data.

Linux Device Drivers 2nd edition states: "Normally, a wake_up call can cause an immediate reschedule to happen, meaning that other processes might run before wake_up returns." ... which would match the behaviour observed.

Change to keeping two krefs on each request. One for the caller, and one for xenbus_thread. Each will kref_put() when finished, and the last will free it.

This use of kref matches the description in Documentation/core-api/kref.rst

CVSS Base Scores

version 3.1