{"id":"DEBIAN-CVE-2022-49300","details":"In the Linux kernel, the following vulnerability has been resolved:  nbd: fix race between nbd_alloc_config() and module removal  When nbd module is being removing, nbd_alloc_config() may be called concurrently by nbd_genl_connect(), although try_module_get() will return false, but nbd_alloc_config() doesn't handle it.  The race may lead to the leak of nbd_config and its related resources (e.g, recv_workq) and oops in nbd_read_stat() due to the unload of nbd module as shown below:    BUG: kernel NULL pointer dereference, address: 0000000000000040   Oops: 0000 [#1] SMP PTI   CPU: 5 PID: 13840 Comm: kworker/u17:33 Not tainted 5.14.0+ #1   Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)   Workqueue: knbd16-recv recv_work [nbd]   RIP: 0010:nbd_read_stat.cold+0x130/0x1a4 [nbd]   Call Trace:    recv_work+0x3b/0xb0 [nbd]    process_one_work+0x1ed/0x390    worker_thread+0x4a/0x3d0    kthread+0x12a/0x150    ret_from_fork+0x22/0x30  Fixing it by checking the return value of try_module_get() in nbd_alloc_config(). As nbd_alloc_config() may return ERR_PTR(-ENODEV), assign nbd-\u003econfig only when nbd_alloc_config() succeeds to ensure the value of nbd-\u003econfig is binary (valid or NULL).  Also adding a debug message to check the reference counter of nbd_config during module removal.","modified":"2026-09-01T16:05:30.440131045Z","published":"2025-02-26T07:01:06.830Z","upstream":["CVE-2022-49300"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2022-49300"}],"affected":[{"package":{"name":"linux","ecosystem":"Debian:12","purl":"pkg:deb/debian/linux?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"5.18.5-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2022-49300.json"}},{"package":{"name":"linux","ecosystem":"Debian:13","purl":"pkg:deb/debian/linux?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"5.18.5-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2022-49300.json"}},{"package":{"name":"linux","ecosystem":"Debian:14","purl":"pkg:deb/debian/linux?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"5.18.5-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2022-49300.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H"}]}