Log in Start free

Vulnerability · Published Feb 27, 2025 · Assigned by Linux

CVE-2025-21731nbd: don't allow reconnect after disconnect

High 7.8

In plain English

A high-severity use-after-free in Linux from Linux. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 15% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.8High
Exploit odds (30 days)0.2%top 84.9% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

In the Linux kernel, the following vulnerability has been resolved: nbd: don't allow reconnect after disconnect Following process can cause nbd_config UAF: 1) grab nbd_config temporarily; 2) nbd_genl_disconnect() flush all recv_work() and release the initial reference: nbd_genl_disconnect nbd_disconnect_and_put nbd_disconnect flush_workqueue(nbd->recv_workq) if (test_and_clear_bit(NBD_RT_HAS_CONFIG_REF, ...)) nbd_config_put -> due to step 1), reference is still not zero 3) nbd_genl_reconfigure() queue recv_work() again; nbd_genl_reconfigure config = nbd_get_config_unlocked(nbd) if (!config) -> succeed if (!test_bit(NBD_RT_BOUND, ...)) -> succeed nbd_reconnect_socket queue_work(nbd->recv_workq, &args->work) 4) step 1) release the reference; 5) Finially, recv_work() will trigger UAF: recv_work nbd_config_put(nbd) -> nbd_config is freed atomic_dec(&config->recv_threads) -> UAF Fix the problem by clearing NBD_RT_BOUND in nbd_genl_disconnect(), so that nbd_genl_reconfigure() will fail.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12linux6.1.129-1DEBIAN-CVE-2025-21731
Debian:13linux6.12.13-1DEBIAN-CVE-2025-21731
Debian:14linux6.12.13-1DEBIAN-CVE-2025-21731
Ubuntu:22.04:LTSlinux5.15.0-140.150UBUNTU-CVE-2025-21731
Ubuntu:24.04:LTSlinux6.8.0-64.67UBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-aws5.15.0-1084.91UBUNTU-CVE-2025-21731
Ubuntu:24.04:LTSlinux-aws6.8.0-1032.34UBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-aws-6.86.8.0-1032.34~22.04.1UBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-azure5.15.0-1089.98UBUNTU-CVE-2025-21731
Ubuntu:24.04:LTSlinux-azure6.8.0-1034.39UBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2025-21731
Ubuntu:24.04:LTSlinux-azure-6.116.11.0-1015.15~24.04.1UBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-azure-6.86.8.0-1034.39~22.04.1UBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-azure-fde5.15.0-1089.98.1UBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2025-21731
Ubuntu:24.04:LTSlinux-azure-nvidia6.8.0-1022.23UBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-gcp5.15.0-1083.92UBUNTU-CVE-2025-21731
Ubuntu:24.04:LTSlinux-gcp6.8.0-1033.35UBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2025-21731
Ubuntu:24.04:LTSlinux-gcp-6.116.11.0-1015.15~24.04.1UBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-gcp-6.86.8.0-1033.35~22.04.1UBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-gke5.15.0-1081.87UBUNTU-CVE-2025-21731
Ubuntu:24.04:LTSlinux-gke6.8.0-1028.32UBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-gkeop5.15.0-1066.74UBUNTU-CVE-2025-21731
Ubuntu:24.04:LTSlinux-gkeop6.8.0-1015.17UBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2025-21731
Ubuntu:24.04:LTSlinux-hwe-6.116.11.0-26.26~24.04.1UBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-hwe-6.5no fix listedUBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-hwe-6.86.8.0-64.67~22.04.1UBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-ibm5.15.0-1076.79UBUNTU-CVE-2025-21731
Ubuntu:24.04:LTSlinux-ibm6.8.0-1029.29UBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-ibm-6.86.8.0-1029.29~22.04.1UBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-intel-iotg5.15.0-1079.85UBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-kvm5.15.0-1080.85UBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-lowlatency5.15.0-140.150UBUNTU-CVE-2025-21731
Ubuntu:24.04:LTSlinux-lowlatency6.8.0-64.67.1UBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2025-21731
Ubuntu:24.04:LTSlinux-lowlatency-hwe-6.116.11.0-1014.15~24.04.1UBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.5no fix listedUBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.86.8.0-64.67.1~22.04.1UBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-nvidia5.15.0-1078.79UBUNTU-CVE-2025-21731
Ubuntu:24.04:LTSlinux-nvidia6.8.0-1031.34UBUNTU-CVE-2025-21731
Ubuntu:24.04:LTSlinux-nvidia-6.116.11.0-1010.10UBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-nvidia-6.5no fix listedUBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-nvidia-6.86.8.0-1031.34~22.04.1UBUNTU-CVE-2025-21731
Ubuntu:24.04:LTSlinux-nvidia-lowlatency6.8.0-1031.34.1UBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-nvidia-tegra5.15.0-1037.37UBUNTU-CVE-2025-21731
Ubuntu:24.04:LTSlinux-nvidia-tegra6.8.0-1008.8UBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-nvidia-tegra-igx5.15.0-1026.26UBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2025-21731
Ubuntu:24.04:LTSlinux-oem-6.116.11.0-1022.22UBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-oem-6.5no fix listedUBUNTU-CVE-2025-21731
Ubuntu:24.04:LTSlinux-oem-6.86.8.0-1031.31UBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-oracle5.15.0-1081.87UBUNTU-CVE-2025-21731
Ubuntu:24.04:LTSlinux-oracle6.8.0-1029.30UBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-oracle-6.5no fix listedUBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-oracle-6.86.8.0-1029.30~22.04.1UBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-raspi5.15.0-1078.81UBUNTU-CVE-2025-21731
Ubuntu:24.04:LTSlinux-raspi6.8.0-1031.35UBUNTU-CVE-2025-21731
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2025-21731
Ubuntu:24.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2025-21731
Ubuntu:24.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-riscv-6.5no fix listedUBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-riscv-6.86.8.0-64.67~22.04.1UBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-starfive-6.5no fix listedUBUNTU-CVE-2025-21731
Ubuntu:24.04:LTSlinux-xilinx6.8.0-1017.18UBUNTU-CVE-2025-21731
Ubuntu:22.04:LTSlinux-xilinx-zynqmp5.15.0-1050.54UBUNTU-CVE-2025-21731

Affected products (as reported)

VendorProductVersions
Linux Linux b7aa3d39385dc2d95899f9e379623fef446a2acd – before e70a578487a47d7cf058904141e586684d1c3381b7aa3d39385dc2d95899f9e379623fef446a2acd – before 6bef6222a3f6c7adb6396f77f25a3579d821b09ab7aa3d39385dc2d95899f9e379623fef446a2acd – before e3be8862d73cac833e0fb7602636c19c6cb94b11b7aa3d39385dc2d95899f9e379623fef446a2acd – before e7343fa33751cb07c1c56b666bf37cfca357130eb7aa3d39385dc2d95899f9e379623fef446a2acd – before d208d2c52b652913b5eefc8ca434b0d6b757f68fb7aa3d39385dc2d95899f9e379623fef446a2acd – before a8ee6ecde2b7bfb58c8a3afe8a9d2b848f580739b7aa3d39385dc2d95899f9e379623fef446a2acd – before 9793bd5ae4bdbdb2dde401a3cab94a6bfd05e302b7aa3d39385dc2d95899f9e379623fef446a2acd – before 844b8cdc681612ff24df62cdefddeab5772fadf1
Linux Linux 4.12

Weakness: CWE-416 · Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

References