{"id":"CVE-2025-37949","revision":"286887d3be2b4fd9aec584cbc7cc8f68","records":[{"revision":"286887d3be2b4fd9aec584cbc7cc8f68","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2025-37949","aliases":[],"title":"xenbus: Use kref to track req lifetime","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nxenbus: Use kref to track req lifetime\n\nMarek reported seeing a NULL pointer fault in the xenbus_thread\ncallstack:\nBUG: kernel NULL pointer dereference, address: 0000000000000000\nRIP: e030:__wake_up_common+0x4c/0x180\nCall Trace:\n <TASK>\n __wake_up_common_lock+0x82/0xd0\n process_msg+0x18e/0x2f0\n xenbus_thread+0x165/0x1c0\n\nprocess_msg+0x18e is req->cb(req).  req->cb is set to xs_wake_up(), a\nthin wrapper around wake_up(), or xenbus_dev_queue_reply().  It seems\nlike it was xs_wake_up() in this case.\n\nIt seems like req may have woken up the xs_wait_for_reply(), which\nkfree()ed the req.  When xenbus_thread resumes, it faults on the zero-ed\ndata.\n\nLinux Device Drivers 2nd edition states:\n\"Normally, a wake_up call can cause an immediate reschedule to happen,\nmeaning that other processes might run before wake_up returns.\"\n... which would match the behaviour observed.\n\nChange to keeping two krefs on each request.  One for the caller, and\none for xenbus_thread.  Each will kref_put() when finished, and the last\nwill free it.\n\nThis use of kref matches the description in\nDocumentation/core-api/kref.rst","state":0,"publishedAt":"2025-05-20T16:01:45.242+00:00","modifiedAt":"2026-10-15T21:52:04.919+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"drivers/xen/xenbus/xenbus.h\",\n                        \"drivers/xen/xenbus/xenbus_comms.c\",\n                        \"drivers/xen/xenbus/xenbus_dev_frontend.c\",\n                        \"drivers/xen/xenbus/xenbus_xs.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"fd8aa9095a95c02dcc35540a263267c29b8fda9d\",\n                            \"lessThan\": \"0e94a246bb6d9538010b6c02d2b1d4717a97b2e5\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"fd8aa9095a95c02dcc35540a263267c29b8fda9d\",\n                            \"lessThan\": \"f1bcac367bc95631afbb918348f30dec887d0e1b\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"fd8aa9095a95c02dcc35540a263267c29b8fda9d\",\n                            \"lessThan\": \"4d260a5558df4650eb87bc41b2c9ac2d6b2ba447\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"fd8aa9095a95c02dcc35540a263267c29b8fda9d\",\n                            \"lessThan\": \"8b02f85e84dc6f7c150cef40ddb69af5a25659e5\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"fd8aa9095a95c02dcc35540a263267c29b8fda9d\",\n                            \"lessThan\": \"cbfaf46b88a4c01b64c4186cdccd766c19ae644c\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"fd8aa9095a95c02dcc35540a263267c29b8fda9d\",\n                            \"lessThan\": \"8e9c8a0393b5f85f1820c565ab8105660f4e8f92\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"fd8aa9095a95c02dcc35540a263267c29b8fda9d\",\n                            \"lessThan\": \"2466b0f66795c3c426cacc8998499f38031dbb59\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"fd8aa9095a95c02dcc35540a263267c29b8fda9d\",\n                            \"lessThan\": \"1f0304dfd9d217c2f8b04a9ef4b3258a66eedd27\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"affected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"drivers/xen/xenbus/xenbus.h\",\n                        \"drivers/xen/xenbus/xenbus_comms.c\",\n                        \"drivers/xen/xenbus/xenbus_dev_frontend.c\",\n                        \"drivers/xen/xenbus/xenbus_xs.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"4.11\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"4.11\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.4.294\",\n                            \"lessThanOrEqual\": \"5.4.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.10.238\",\n                            \"lessThanOrEqual\": \"5.10.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.15.183\",\n                            \"lessThanOrEqual\": \"5.15.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.1.139\",\n                            \"lessThanOrEqual\": \"6.1.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.6.91\",\n                            \"lessThanOrEqual\": \"6.6.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.29\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.14.7\",\n                            \"lessThanOrEqual\": \"6.14.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.15\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8,"severity":"HIGH"}],"references":["https://git.kernel.org/stable/c/0e94a246bb6d9538010b6c02d2b1d4717a97b2e5","https://git.kernel.org/stable/c/f1bcac367bc95631afbb918348f30dec887d0e1b","https://git.kernel.org/stable/c/4d260a5558df4650eb87bc41b2c9ac2d6b2ba447","https://git.kernel.org/stable/c/8b02f85e84dc6f7c150cef40ddb69af5a25659e5","https://git.kernel.org/stable/c/cbfaf46b88a4c01b64c4186cdccd766c19ae644c","https://git.kernel.org/stable/c/8e9c8a0393b5f85f1820c565ab8105660f4e8f92","https://git.kernel.org/stable/c/2466b0f66795c3c426cacc8998499f38031dbb59","https://git.kernel.org/stable/c/1f0304dfd9d217c2f8b04a9ef4b3258a66eedd27"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2025-37949","license":"CVE Program Terms of Use","key":"cve-program:CVE-2025-37949","identifiers":["CVE-2025-37949"]},"retained":false,"historicalAffected":[]}],"coverage":[]}