cbcvebase.
CVE-2025-37949
published 2025-05-20

CVE-2025-37949: 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…

PriorityP421medium5.5CVSS 3.1
AVLACLPRLUINSUCNINAH
EPSS
0.18%
7.3th percentile
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: __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

Affected

39 ranges· showing 25
VendorProductVersion rangeFixed in
debiandebian_linux
debianlinux< linux 6.1.140-1 (bookworm)linux 6.1.140-1 (bookworm)
debianlinux-6.1< linux 6.1.140-1 (bookworm)linux 6.1.140-1 (bookworm)
linuxlinux
linuxlinux>= fd8aa9095a95c02dcc35540a263267c29b8fda9d < 0e94a246bb6d9538010b6c02d2b1d4717a97b2e50e94a246bb6d9538010b6c02d2b1d4717a97b2e5
linuxlinux>= fd8aa9095a95c02dcc35540a263267c29b8fda9d < f1bcac367bc95631afbb918348f30dec887d0e1bf1bcac367bc95631afbb918348f30dec887d0e1b
linuxlinux>= fd8aa9095a95c02dcc35540a263267c29b8fda9d < 4d260a5558df4650eb87bc41b2c9ac2d6b2ba4474d260a5558df4650eb87bc41b2c9ac2d6b2ba447
linuxlinux>= fd8aa9095a95c02dcc35540a263267c29b8fda9d < 8b02f85e84dc6f7c150cef40ddb69af5a25659e58b02f85e84dc6f7c150cef40ddb69af5a25659e5
linuxlinux>= fd8aa9095a95c02dcc35540a263267c29b8fda9d < cbfaf46b88a4c01b64c4186cdccd766c19ae644ccbfaf46b88a4c01b64c4186cdccd766c19ae644c
linuxlinux>= fd8aa9095a95c02dcc35540a263267c29b8fda9d < 8e9c8a0393b5f85f1820c565ab8105660f4e8f928e9c8a0393b5f85f1820c565ab8105660f4e8f92
linuxlinux>= fd8aa9095a95c02dcc35540a263267c29b8fda9d < 2466b0f66795c3c426cacc8998499f38031dbb592466b0f66795c3c426cacc8998499f38031dbb59
linuxlinux>= fd8aa9095a95c02dcc35540a263267c29b8fda9d < 1f0304dfd9d217c2f8b04a9ef4b3258a66eedd271f0304dfd9d217c2f8b04a9ef4b3258a66eedd27
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel>= 0 < 5.10.244-15.10.244-1
linuxlinux_kernel>= 0 < 6.1.140-16.1.140-1
linuxlinux_kernel>= 0 < 6.12.29-16.12.29-1
linuxlinux_kernel>= 0 < 6.12.29-16.12.29-1
linuxlinux_kernel>= 0 < 5.15.0-144.1575.15.0-144.157
linuxlinux_kernel>= 0 < 6.8.0-100.1006.8.0-100.100
linuxlinux_kernel>= 4.11 < 5.4.2945.4.294
linuxlinux_kernel>= 5.11 < 5.15.1835.15.183

CVSS provenance

nvdv3.15.5MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
osv8.8HIGH
vendor_ubuntu8.8HIGH
vendor_debian5.5MEDIUM
vendor_redhat5.5MEDIUM
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