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Vulnerability · Published May 20, 2025 · Assigned by Linux

CVE-2025-37949xenbus: Use kref to track req lifetime

High 7.8

In plain English

A high-severity security flaw 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 84.8% 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: xenbus: Use kref to track req lifetime Marek reported seeing a NULL pointer fault in the xenbus_thread callstack: BUG: kernel NULL pointer dereference, address: 0000000000000000 RIP: e030:__wake_up_common+0x4c/0x180 Call Trace: <TASK> __wake_up_common_lock+0x82/0xd0 process_msg+0x18e/0x2f0 xenbus_thread+0x165/0x1c0 process_msg+0x18e is req->cb(req). req->cb is set to xs_wake_up(), a thin wrapper around wake_up(), or xenbus_dev_queue_reply(). It seems like it was xs_wake_up() in this case. It seems like req may have woken up the xs_wait_for_reply(), which kfree()ed the req. When xenbus_thread resumes, it faults on the zero-ed data. Linux Device Drivers 2nd edition states: "Normally, a wake_up call can cause an immediate reschedule to happen, meaning that other processes might run before wake_up returns." ... which would match the behaviour observed. Change to keeping two krefs on each request. One for the caller, and one for xenbus_thread. Each will kref_put() when finished, and the last will free it. This use of kref matches the description in Documentation/core-api/kref.rst

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12linux6.1.140-1DEBIAN-CVE-2025-37949
Debian:12linux6.1.140-1DSA-5925-1
Debian:13linux6.12.29-1DEBIAN-CVE-2025-37949
Debian:14linux6.12.29-1DEBIAN-CVE-2025-37949
Ubuntu:22.04:LTSlinux5.15.0-144.157UBUNTU-CVE-2025-37949
Ubuntu:24.04:LTSlinux6.8.0-100.100UBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-aws5.15.0-1088.95UBUNTU-CVE-2025-37949
Ubuntu:24.04:LTSlinux-aws6.8.0-1046.49UBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2025-37949
Ubuntu:24.04:LTSlinux-aws-6.146.14.0-1011.11~24.04.1UBUNTU-CVE-2025-37949
Ubuntu:24.04:LTSlinux-aws-6.146.14.0-1011.11~24.04.1USN-7699-1
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-aws-6.86.8.0-1046.49~22.04.1UBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-azure5.15.0-1094.103UBUNTU-CVE-2025-37949
Ubuntu:24.04:LTSlinux-azure6.8.0-1046.52UBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2025-37949
Ubuntu:24.04:LTSlinux-azure-6.11no fix listedUBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-azure-6.86.8.0-1051.57~22.04.1UBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-azure-fde5.15.0-1094.103.1UBUNTU-CVE-2025-37949
Ubuntu:24.04:LTSlinux-azure-fde6.8.0-1046.53UBUNTU-CVE-2025-37949
Ubuntu:25.10linux-azure-fdeno fix listedUBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-azure-fde-6.86.8.0-1046.53~22.04.1UBUNTU-CVE-2025-37949
Ubuntu:24.04:LTSlinux-azure-nvidiano fix listedUBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-gcp5.15.0-1087.96UBUNTU-CVE-2025-37949
Ubuntu:24.04:LTSlinux-gcp6.8.0-1047.50UBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2025-37949
Ubuntu:24.04:LTSlinux-gcp-6.11no fix listedUBUNTU-CVE-2025-37949
Ubuntu:24.04:LTSlinux-gcp-6.146.14.0-1014.15~24.04.1USN-7699-1
Ubuntu:24.04:LTSlinux-gcp-6.146.14.0-1014.15~24.04.1UBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-gcp-6.86.8.0-1047.50~22.04.2UBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-gke5.15.0-1085.91UBUNTU-CVE-2025-37949
Ubuntu:24.04:LTSlinux-gke6.8.0-1043.48UBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-gkeop5.15.0-1070.78UBUNTU-CVE-2025-37949
Ubuntu:24.04:LTSlinux-gkeop6.8.0-1030.33UBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2025-37949
Ubuntu:24.04:LTSlinux-hwe-6.11no fix listedUBUNTU-CVE-2025-37949
Ubuntu:24.04:LTSlinux-hwe-6.146.14.0-28.28~24.04.1USN-7699-2
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-hwe-6.5no fix listedUBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-hwe-6.86.8.0-100.100~22.04.1UBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-ibm5.15.0-1080.83UBUNTU-CVE-2025-37949
Ubuntu:24.04:LTSlinux-ibm6.8.0-1044.44UBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-ibm-6.86.8.0-1044.44~22.04.1UBUNTU-CVE-2025-37949
Ubuntu:24.04:LTSlinux-intelno fix listedUBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-intel-iotg5.15.0-1083.89UBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-kvm5.15.0-1084.89UBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-lowlatency5.15.0-144.157UBUNTU-CVE-2025-37949
Ubuntu:24.04:LTSlinux-lowlatency6.8.0-100.100.1UBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2025-37949
Ubuntu:24.04:LTSlinux-lowlatency-hwe-6.11no fix listedUBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.5no fix listedUBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.86.8.0-100.100.1~22.04.1UBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-nvidia5.15.0-1082.83UBUNTU-CVE-2025-37949
Ubuntu:24.04:LTSlinux-nvidia6.8.0-1046.49UBUNTU-CVE-2025-37949
Ubuntu:24.04:LTSlinux-nvidia-6.11no fix listedUBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-nvidia-6.5no fix listedUBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-nvidia-6.86.8.0-1046.49~22.04.1UBUNTU-CVE-2025-37949
Ubuntu:24.04:LTSlinux-nvidia-lowlatency6.8.0-1046.49.1UBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-nvidia-tegra5.15.0-1041.41UBUNTU-CVE-2025-37949
Ubuntu:24.04:LTSlinux-nvidia-tegra6.8.0-1020.20UBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-nvidia-tegra-igx5.15.0-1030.30UBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2025-37949
Ubuntu:24.04:LTSlinux-oem-6.11no fix listedUBUNTU-CVE-2025-37949
Ubuntu:24.04:LTSlinux-oem-6.146.14.0-1010.10UBUNTU-CVE-2025-37949
Ubuntu:24.04:LTSlinux-oem-6.146.14.0-1010.10USN-7699-2
Ubuntu:22.04:LTSlinux-oem-6.5no fix listedUBUNTU-CVE-2025-37949
Ubuntu:24.04:LTSlinux-oem-6.8no fix listedUBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-oracle5.15.0-1085.91UBUNTU-CVE-2025-37949
Ubuntu:24.04:LTSlinux-oracle6.8.0-1043.44UBUNTU-CVE-2025-37949
Ubuntu:24.04:LTSlinux-oracle-6.146.14.0-1011.11~24.04.1USN-7699-1
Ubuntu:24.04:LTSlinux-oracle-6.146.14.0-1011.11~24.04.1UBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-oracle-6.5no fix listedUBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-oracle-6.86.8.0-1043.44~22.04.1UBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-raspi5.15.0-1083.86UBUNTU-CVE-2025-37949
Ubuntu:24.04:LTSlinux-raspi6.8.0-1047.51UBUNTU-CVE-2025-37949
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2025-37949
Ubuntu:24.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2025-37949
Ubuntu:24.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2025-37949
Ubuntu:24.04:LTSlinux-riscv-6.146.14.0-28.28.1~24.04.1UBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-riscv-6.5no fix listedUBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-riscv-6.86.8.0-100.100~22.04.1UBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-starfive-6.5no fix listedUBUNTU-CVE-2025-37949
Ubuntu:24.04:LTSlinux-xilinx6.8.0-1023.24UBUNTU-CVE-2025-37949
Ubuntu:22.04:LTSlinux-xilinx-zynqmp5.15.0-1052.56UBUNTU-CVE-2025-37949

Affected products (as reported)

VendorProductVersions
Linux Linux fd8aa9095a95c02dcc35540a263267c29b8fda9d – before 0e94a246bb6d9538010b6c02d2b1d4717a97b2e5fd8aa9095a95c02dcc35540a263267c29b8fda9d – before f1bcac367bc95631afbb918348f30dec887d0e1bfd8aa9095a95c02dcc35540a263267c29b8fda9d – before 4d260a5558df4650eb87bc41b2c9ac2d6b2ba447fd8aa9095a95c02dcc35540a263267c29b8fda9d – before 8b02f85e84dc6f7c150cef40ddb69af5a25659e5fd8aa9095a95c02dcc35540a263267c29b8fda9d – before cbfaf46b88a4c01b64c4186cdccd766c19ae644cfd8aa9095a95c02dcc35540a263267c29b8fda9d – before 8e9c8a0393b5f85f1820c565ab8105660f4e8f92fd8aa9095a95c02dcc35540a263267c29b8fda9d – before 2466b0f66795c3c426cacc8998499f38031dbb59fd8aa9095a95c02dcc35540a263267c29b8fda9d – before 1f0304dfd9d217c2f8b04a9ef4b3258a66eedd27
Linux Linux 4.11

References