CVE-2025-37949xenbus: Use kref to track req lifetime
Updated under an hour ago ()
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It affects Linux and 2 other products. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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
- 7.8 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Modified
- Record last updated
- Oct 15, 2026
- First seen by InfoSec Signals
- Oct 15, 2026
Affected products
Linux Linux linux:linux (from the name) | from fd8aa9095a95c02dcc35540a263267c29b8fda9d before 0e94a246bb6d9538010b6c02d2b1d4717a97b2e5; from fd8aa9095a95c02dcc35540a263267c29b8fda9d before f1bcac367bc95631afbb918348f30dec887d0e1b; from fd8aa9095a95c02dcc35540a263267c29b8fda9d before 4d260a5558df4650eb87bc41b2c9ac2d6b2ba447; from fd8aa9095a95c02dcc35540a263267c29b8fda9d before 8b02f85e84dc6f7c150cef40ddb69af5a25659e5; from fd8aa9095a95c02dcc35540a263267c29b8fda9d before cbfaf46b88a4c01b64c4186cdccd766c19ae644c; from fd8aa9095a95c02dcc35540a263267c29b8fda9d before 8e9c8a0393b5f85f1820c565ab8105660f4e8f92; from fd8aa9095a95c02dcc35540a263267c29b8fda9d before 2466b0f66795c3c426cacc8998499f38031dbb59; from fd8aa9095a95c02dcc35540a263267c29b8fda9d before 1f0304dfd9d217c2f8b04a9ef4b3258a66eedd27 | CNA record |
linux linux_kernel linux:linux_kernel | from 4.11 before 5.4.294; from 5.5 before 5.10.238; from 5.11 before 5.15.183; from 5.16 before 6.1.139; from 6.2 before 6.6.91; from 6.7 before 6.12.29; from 6.13 before 6.14.7; 6.15; and 4 more ranges | NVD |
debian debian_linux debian:debian_linux | 11.0 | NVD |
References
- https://git.kernel.org/stable/c/0e94a246bb6d9538010b6c02d2b1d4717a97b2e5patch
- https://git.kernel.org/stable/c/f1bcac367bc95631afbb918348f30dec887d0e1bpatch
- https://git.kernel.org/stable/c/4d260a5558df4650eb87bc41b2c9ac2d6b2ba447patch
- https://git.kernel.org/stable/c/8b02f85e84dc6f7c150cef40ddb69af5a25659e5patch
- https://git.kernel.org/stable/c/cbfaf46b88a4c01b64c4186cdccd766c19ae644cpatch
- https://git.kernel.org/stable/c/8e9c8a0393b5f85f1820c565ab8105660f4e8f92patch
- https://git.kernel.org/stable/c/2466b0f66795c3c426cacc8998499f38031dbb59patch
- https://git.kernel.org/stable/c/1f0304dfd9d217c2f8b04a9ef4b3258a66eedd27patch
- https://lists.debian.org/debian-lts-announce/2025/08/msg00010.htmlthird-party-advisory
- https://lists.debian.org/debian-lts-announce/2025/10/msg00007.htmlthird-party-advisory
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.