CVE - CVE-2025-37949

CVE-ID
CVE-2025-37949	Learn more at National Vulnerability Database (NVD) • CVSS Severity Rating • Fix Information • Vulnerable Software Versions • SCAP Mappings • CPE Information
Description
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
References
Note: References are provided for the convenience of the reader to help distinguish between vulnerabilities. The list is not intended to be complete.
MISC:https://git.kernel.org/stable/c/0e94a246bb6d9538010b6c02d2b1d4717a97b2e5 URL:https://git.kernel.org/stable/c/0e94a246bb6d9538010b6c02d2b1d4717a97b2e5 MISC:https://git.kernel.org/stable/c/1f0304dfd9d217c2f8b04a9ef4b3258a66eedd27 URL:https://git.kernel.org/stable/c/1f0304dfd9d217c2f8b04a9ef4b3258a66eedd27 MISC:https://git.kernel.org/stable/c/2466b0f66795c3c426cacc8998499f38031dbb59 URL:https://git.kernel.org/stable/c/2466b0f66795c3c426cacc8998499f38031dbb59 MISC:https://git.kernel.org/stable/c/4d260a5558df4650eb87bc41b2c9ac2d6b2ba447 URL:https://git.kernel.org/stable/c/4d260a5558df4650eb87bc41b2c9ac2d6b2ba447 MISC:https://git.kernel.org/stable/c/8b02f85e84dc6f7c150cef40ddb69af5a25659e5 URL:https://git.kernel.org/stable/c/8b02f85e84dc6f7c150cef40ddb69af5a25659e5 MISC:https://git.kernel.org/stable/c/8e9c8a0393b5f85f1820c565ab8105660f4e8f92 URL:https://git.kernel.org/stable/c/8e9c8a0393b5f85f1820c565ab8105660f4e8f92 MISC:https://git.kernel.org/stable/c/cbfaf46b88a4c01b64c4186cdccd766c19ae644c URL:https://git.kernel.org/stable/c/cbfaf46b88a4c01b64c4186cdccd766c19ae644c MISC:https://git.kernel.org/stable/c/f1bcac367bc95631afbb918348f30dec887d0e1b URL:https://git.kernel.org/stable/c/f1bcac367bc95631afbb918348f30dec887d0e1b
Assigning CNA
kernel.org
Date Record Created
20250416	Disclaimer: The record creation date may reflect when the CVE ID was allocated or reserved, and does not necessarily indicate when this vulnerability was discovered, shared with the affected vendor, publicly disclosed, or updated in CVE.
Phase (Legacy)
Assigned (20250416)
Votes (Legacy)

Comments (Legacy)

Proposed (Legacy)
N/A
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