Answer in brief
CVE-2025-37949 records a Unknown severity 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.
Answer in brief
CVE-2025-37949 records a Unknown severity 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.
A CVSS score is not reported in the current record. 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.
| 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
Aug 5, 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.
A CVSS score is not reported in the current record. 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.
| 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
Aug 5, 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.