Answer in brief
CVE-2025-37949 records a High severity (CVSS 7.8) vulnerability in xenbus: Use kref to track req lifetime. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 7.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Product | Affected versions | Fixed versions |
|---|---|---|
| cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:6.15:rc1:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:6.15:rc2:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:6.15:rc3:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:6.15:rc4:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:6.15:rc5:*:*:*:*:*:* | Not reported | Not reported |
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | 4.11 | Not reported |
| Linux/Linuxgeneric | >=fd8aa9095a95c02dcc35540a263267c29b8fda9d <0e94a246bb6d9538010b6c02d2b1d4717a97b2e5 || >=fd8aa9095a95c02dcc35540a263267c29b8fda9d <f1bcac367bc95631afbb918348f30dec887d0e1b || >=fd8aa9095a95c02dcc35540a263267c29b8fda9d <4d260a5558df4650eb87bc41b2c9ac2d6b2ba447 || >=fd8aa9095a95c02dcc35540a263267c29b8fda9d <8b02f85e84dc6f7c150cef40ddb69af5a25659e5 || >=fd8aa9095a95c02dcc35540a263267c29b8fda9d <cbfaf46b88a4c01b64c4186cdccd766c19ae644c || >=fd8aa9095a95c02dcc35540a263267c29b8fda9d <8e9c8a0393b5f85f1820c565ab8105660f4e8f92 || >=fd8aa9095a95c02dcc35540a263267c29b8fda9d <2466b0f66795c3c426cacc8998499f38031dbb59 || >=fd8aa9095a95c02dcc35540a263267c29b8fda9d <1f0304dfd9d217c2f8b04a9ef4b3258a66eedd27 | 0e94a246bb6d9538010b6c02d2b1d4717a97b2e5, f1bcac367bc95631afbb918348f30dec887d0e1b, 4d260a5558df4650eb87bc41b2c9ac2d6b2ba447, 8b02f85e84dc6f7c150cef40ddb69af5a25659e5, cbfaf46b88a4c01b64c4186cdccd766c19ae644c, 8e9c8a0393b5f85f1820c565ab8105660f4e8f92, 2466b0f66795c3c426cacc8998499f38031dbb59, 1f0304dfd9d217c2f8b04a9ef4b3258a66eedd27 |
Published upstream
May 20, 2025
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 15, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 5, 2026
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
Quoted source text, attributed separately from HOL analysis.