{"cve":"CVE-2025-68366","nvd":{"published":"2025-12-24T11:16:00.163","modified":"2026-10-13T11:10:00.203","status":"Deferred","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnbd: defer config unlock in nbd_genl_connect\n\nThere is one use-after-free warning when running NBD_CMD_CONNECT and\nNBD_CLEAR_SOCK:\n\nnbd_genl_connect\n  nbd_alloc_and_init_config // config_refs=1\n  nbd_start_device // config_refs=2\n  set NBD_RT_HAS_CONFIG_REF\t\t\topen nbd // config_refs=3\n  recv_work done // config_refs=2\n\t\t\t\t\t\tNBD_CLEAR_SOCK // config_refs=1\n\t\t\t\t\t\tclose nbd // config_refs=0\n  refcount_inc -> uaf\n\n------------[ cut here ]------------\nrefcount_t: addition on 0; use-after-free.\nWARNING: CPU: 24 PID: 1014 at lib/refcount.c:25 refcount_warn_saturate+0x12e/0x290\n nbd_genl_connect+0x16d0/0x1ab0\n genl_family_rcv_msg_doit+0x1f3/0x310\n genl_rcv_msg+0x44a/0x790\n\nThe issue can be easily reproduced by adding a small delay before\nrefcount_inc(&nbd->config_refs) in nbd_genl_connect():\n\n        mutex_unlock(&nbd->config_lock);\n        if (!ret) {\n                set_bit(NBD_RT_HAS_CONFIG_REF, &config->runtime_flags);\n+               printk(\"before sleep\\n\");\n+               mdelay(5 * 1000);\n+               printk(\"after sleep\\n\");\n                refcount_inc(&nbd->config_refs);\n                nbd_connect_reply(info, nbd->index);\n        }","cvss_v4":null,"cvss_v3":null,"cwes":[],"references":["https://git.kernel.org/stable/c/1649714b930f9ea6233ce0810ba885999da3b5d4","https://git.kernel.org/stable/c/2e5e0665a594f076ef2b9439447bae8be293d09d","https://git.kernel.org/stable/c/330d688a5ca53857828081a3cf31b92ad1b0b3ed","https://git.kernel.org/stable/c/9a38306643874566d20f7aba7dff9e6f657b51a9","https://git.kernel.org/stable/c/ae3e7bc1f4b393ae20e5c85583eb2c6977374716"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:17:07.138532058+00:00"},"epss":{"cve":"CVE-2025-68366","score":0.00198,"percentile":0.09464,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}