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In the Linux kernel, the following vulnerability has been resolved: nbd: defer config unlock in nbd_genl_connect There is one use-after-free warning when running NBD_CMD_CONNECT and NBD_CLEAR_SOCK: nbd_genl_connect nbd_alloc_and_init_config // config_refs=1 nbd_start_device // config_refs=2 set NBD_RT_HAS_CONFIG_REF open nbd // config_refs=3 recv_work done // config_refs=2 NBD_CLEAR_SOCK // config_refs=1 close nbd // config_refs=0 refcount_inc -> uaf ------------[ cut here ]------------ refcount_t: addition on 0; use-after-free. WARNING: CPU: 24 PID: 1014 at lib/refcount.c:25 refcount_warn_saturate+0x12e/0x290 nbd_genl_connect+0x16d0/0x1ab0 genl_family_rcv_msg_doit+0x1f3/0x310 genl_rcv_msg+0x44a/0x790 The issue can be easily reproduced by adding a small delay before refcount_inc(&nbd->config_refs) in nbd_genl_connect(): mutex_unlock(&nbd->config_lock); if (!ret) { set_bit(NBD_RT_HAS_CONFIG_REF, &config->runtime_flags); + printk("before sleep\n"); + mdelay(5 * 1000); + printk("after sleep\n"); refcount_inc(&nbd->config_refs); nbd_connect_reply(info, nbd->index); }
Upstream advisory: https://lore.kernel.org/linux-cve-announce/2025122459-CVE-2025-68366-b367@gregkh/T
This issue has been addressed in the following products: Red Hat Enterprise Linux 9.4 Extended Update Support Via RHSA-2026:21209 https://access.redhat.com/errata/RHSA-2026:21209
This issue has been addressed in the following products: Red Hat Enterprise Linux 9 Via RHSA-2026:21556 https://access.redhat.com/errata/RHSA-2026:21556
This issue has been addressed in the following products: Red Hat Enterprise Linux 9.6 Extended Update Support Via RHSA-2026:23224 https://access.redhat.com/errata/RHSA-2026:23224
This issue has been addressed in the following products: Red Hat Enterprise Linux 10 Via RHSA-2026:23329 https://access.redhat.com/errata/RHSA-2026:23329
This issue has been addressed in the following products: Red Hat Enterprise Linux 10.0 Extended Update Support Via RHSA-2026:24343 https://access.redhat.com/errata/RHSA-2026:24343
This issue has been addressed in the following products: Red Hat Enterprise Linux 8 Via RHSA-2026:25120 https://access.redhat.com/errata/RHSA-2026:25120
This issue has been addressed in the following products: Red Hat Enterprise Linux 8 Via RHSA-2026:25121 https://access.redhat.com/errata/RHSA-2026:25121
This issue has been addressed in the following products: Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support Via RHSA-2026:25533 https://access.redhat.com/errata/RHSA-2026:25533
This issue has been addressed in the following products: Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions Via RHSA-2026:26462 https://access.redhat.com/errata/RHSA-2026:26462
This issue has been addressed in the following products: Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions Via RHSA-2026:26515 https://access.redhat.com/errata/RHSA-2026:26515
This issue has been addressed in the following products: Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On Via RHSA-2026:26535 https://access.redhat.com/errata/RHSA-2026:26535
This issue has been addressed in the following products: Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions Red Hat Enterprise Linux 8.8 Telecommunications Update Service Via RHSA-2026:26563 https://access.redhat.com/errata/RHSA-2026:26563