Description
In the Linux kernel, the following vulnerability has been resolved:
brd: defer automatic disk creation until module initialization succeeds
My colleague Wupeng found the following problems during fault injection:
BUG: unable to handle page fault for address: fffffbfff809d073
PGD 6e648067 P4D 123ec8067 PUD 123ec4067 PMD 100e38067 PTE 0
Oops: Oops: 0000 [#1] PREEMPT SMP KASAN NOPTI
CPU: 5 UID: 0 PID: 755 Comm: modprobe Not tainted 6.12.0-rc3+ #17
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
1.16.1-2.fc37 04/01/2014
RIP: 0010:__asan_load8+0x4c/0xa0
...
Call Trace:
<TASK>
blkdev_put_whole+0x41/0x70
bdev_release+0x1a3/0x250
blkdev_release+0x11/0x20
__fput+0x1d7/0x4a0
task_work_run+0xfc/0x180
syscall_exit_to_user_mode+0x1de/0x1f0
do_syscall_64+0x6b/0x170
entry_SYSCALL_64_after_hwframe+0x76/0x7e
loop_init() is calling loop_add() after __register_blkdev() succeeds and
is ignoring disk_add() failure from loop_add(), for loop_add() failure
is not fatal and successfully created disks are already visible to
bdev_open().
brd_init() is currently calling brd_alloc() before __register_blkdev()
succeeds and is releasing successfully created disks when brd_init()
returns an error. This can cause UAF for the latter two case:
case 1:
T1:
modprobe brd
brd_init
brd_alloc(0) // success
add_disk
disk_scan_partitions
bdev_file_open_by_dev // alloc file
fput // won't free until back to userspace
brd_alloc(1) // failed since mem alloc error inject
// error path for modprobe will release code segment
// back to userspace
__fput
blkdev_release
bdev_release
blkdev_put_whole
bdev->bd_disk->fops->release // fops is freed now, UAF!
case 2:
T1: T2:
modprobe brd
brd_init
brd_alloc(0) // success
open(/dev/ram0)
brd_alloc(1) // fail
// error path for modprobe
close(/dev/ram0)
...
/* UAF! */
bdev->bd_disk->fops->release
Fix this problem by following what loop_init() does. Besides,
reintroduce brd_devices_mutex to help serialize modifications to
brd_list.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Linux | Linux | 5.14 | 5.15.174 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | linux | 6.12.3-1 | — |
| Debian 13 | linux | 6.12.3-1 | — |
| Debian 12 | linux | 6.1.123-1 | — |
| Debian 11 | linux-6.1 | 6.1.128-1~deb11u1 | DLA-4076-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Nvidia-BlueField 22.04 LTS | linux-bluefield | 5.15.0-1062.64 | — |
| Ubuntu 24.04 LTS | linux | 6.8.0-58.60 | USN-7449-1 |
| Ubuntu 24.04 LTS | linux-aws | 6.8.0-1027.29 | USN-7449-1 |
| Ubuntu 24.04 LTS | linux-azure | 6.8.0-1027.32 | USN-7449-1 |
| Ubuntu 24.04 LTS | linux-azure-6.11 | 6.11.0-1012.12~24.04.1 | — |
| Ubuntu 24.04 LTS | linux-azure-nvidia | 6.8.0-1014.15 | USN-7468-1 |
| Ubuntu 24.04 LTS | linux-gcp | 6.8.0-1028.30 | USN-7450-1 |
| Ubuntu 24.04 LTS | linux-gcp-6.11 | 6.11.0-1011.11~24.04.1 | — |
| Ubuntu 24.04 LTS | linux-gke | 6.8.0-1023.27 | USN-7450-1 |
| Ubuntu 24.04 LTS | linux-gkeop | 6.8.0-1010.12 | USN-7450-1 |
| Ubuntu 24.04 LTS | linux-ibm | 6.8.0-1024.24 | USN-7449-1 |
| Ubuntu 24.04 LTS | linux-nvidia | 6.8.0-1026.29 | USN-7449-1 |
| Ubuntu 24.04 LTS | linux-nvidia-6.11 | 6.11.0-1007.7 | — |
| Ubuntu 24.04 LTS | linux-nvidia-lowlatency | 6.8.0-1026.29.1 | USN-7449-1 |
| Ubuntu 24.04 LTS | linux-nvidia-tegra | 6.8.0-1008.8 | — |
| Ubuntu 24.04 LTS | linux-oem-6.11 | 6.11.0-1015.15 | USN-7310-1 |
| Ubuntu 24.04 LTS | linux-oem-6.8 | 6.8.0-1026.26 | USN-7449-1 |
| Ubuntu 24.04 LTS | linux-oracle | 6.8.0-1024.25 | USN-7449-1 |
| Ubuntu 24.04 LTS | linux-raspi | 6.8.0-1028.32 | USN-7524-1 |
| Ubuntu 24.04 LTS | linux-realtime +1 | No fix yet | — |
| Ubuntu 24.04 LTS | linux-riscv +1 | 6.8.0-58.60.1 | USN-7449-1 |
| Ubuntu 24.04 LTS | linux-xilinx | 6.8.0-1017.18 | — |
| Ubuntu 22.04 LTS | linux +1 | 5.15.0-135.146 | USN-7387-1 |
| Ubuntu 22.04 LTS | linux-aws | 5.15.0-1080.87 | USN-7387-1 |
| Ubuntu 22.04 LTS | linux-aws-6.8 | 6.8.0-1027.29~22.04.1 | USN-7451-1 |
| Ubuntu 22.04 LTS | linux-azure | 5.15.0-1084.93 | USN-7387-1 |
| Ubuntu 22.04 LTS | linux-azure-6.8 | 6.8.0-1027.32~22.04.1 | USN-7449-1 |
| Ubuntu 22.04 LTS | linux-azure-fde | 5.15.0-1084.93.1 | — |
| Ubuntu 22.04 LTS | linux-gcp | 5.15.0-1079.88 | USN-7387-1 |
| Ubuntu 22.04 LTS | linux-gcp-6.8 | 6.8.0-1028.30~22.04.1 | USN-7452-1 |
| Ubuntu 22.04 LTS | linux-gke +1 | 5.15.0-1077.83 | USN-7387-1 |
| Ubuntu 22.04 LTS | linux-gkeop | 5.15.0-1062.70 | USN-7387-1 |
| Ubuntu 22.04 LTS | linux-hwe-6.8 | 6.8.0-58.60~22.04.1 | USN-7449-2 |
| Ubuntu 22.04 LTS | linux-ibm | 5.15.0-1072.75 | USN-7387-1 |
| Ubuntu 22.04 LTS | linux-ibm-6.8 | 6.8.0-1024.24~22.04.1 | — |
| Ubuntu 22.04 LTS | linux-intel-iot-realtime | 5.15.0-1073.75 | — |
| Ubuntu 22.04 LTS | linux-intel-iotg | 5.15.0-1075.81 | USN-7387-1 |
| Ubuntu 22.04 LTS | linux-kvm | 5.15.0-1076.81 | USN-7388-1 |
| Ubuntu 22.04 LTS | linux-nvidia | 5.15.0-1074.75 | USN-7387-1 |
| Ubuntu 22.04 LTS | linux-nvidia-6.8 | 6.8.0-1026.29~22.04.1 | USN-7449-1 |
| Ubuntu 22.04 LTS | linux-nvidia-tegra | 5.15.0-1033.33 | USN-7389-1 |
| Ubuntu 22.04 LTS | linux-nvidia-tegra-igx | 5.15.0-1021.21 | USN-7389-1 |
| Ubuntu 22.04 LTS | linux-oracle-6.8 | 6.8.0-1024.25~22.04.1 | USN-7449-1 |
| Ubuntu 22.04 LTS | linux-raspi | 5.15.0-1074.77 | USN-7387-1 |
| Ubuntu 22.04 LTS | linux-riscv +31 | No fix yet | — |
| Ubuntu 22.04 LTS | linux-riscv-6.8 +1 | 6.8.0-58.60.1~22.04.1 | USN-7449-1 |
| Ubuntu 22.04 LTS | linux-xilinx-zynqmp | 5.15.0-1044.48 | USN-7390-1 |
| Ubuntu 20.04 LTS | linux-aws-5.15 | 5.15.0-1080.87~20.04.1 | USN-7388-1 |
| Ubuntu 20.04 LTS | linux-azure-5.15 | 5.15.0-1086.95~20.04.1 | USN-7421-1 |
| Ubuntu 20.04 LTS | linux-azure-fde-5.15 | 5.15.0-1086.95~20.04.1.1 | USN-7421-1 |
| Ubuntu 20.04 LTS | linux-gcp-5.15 | 5.15.0-1081.90~20.04.1 | USN-7459-2 |
| Ubuntu 20.04 LTS | linux-gke +28 | No fix yet | — |
| Ubuntu 20.04 LTS | linux-hwe-5.15 | 5.15.0-136.147~20.04.1 | USN-7407-1 |
| Ubuntu 20.04 LTS | linux-ibm-5.15 | 5.15.0-1074.77~20.04.1 | USN-7458-1 |
| Ubuntu 20.04 LTS | linux-lowlatency-hwe-5.15 | 5.15.0-135.146~20.04.1 | USN-7387-1 |
| Ubuntu 20.04 LTS | linux-oracle-5.15 +1 | 5.15.0-1077.83~20.04.1 | USN-7459-1, USN-7387-1 |
| Ubuntu 20.04 LTS | linux-riscv-5.15 | 5.15.0-1075.79~20.04.1 | — |
| Ubuntu 18.04 LTS | linux-gcp +14 | No fix yet | — |
Show 7 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 16.04 LTS | linux-hwe-edge | No fix yet | — |
| Ubuntu Pro Realtime 24.04 LTS | linux-raspi-realtime | 6.8.0-2023.24 | USN-7523-1 |
| Ubuntu Pro Realtime 24.04 LTS | linux-realtime | 6.8.1-1020.21 | USN-7453-1 |
| Ubuntu Pro Realtime 22.04 LTS | linux-intel-iot-realtime | 5.15.0-1073.75 | USN-7387-3 |
| Ubuntu Pro Realtime 22.04 LTS | linux-realtime | 5.15.0-1080.88 | USN-7387-3 |
| Ubuntu Pro Realtime 22.04 LTS | linux-realtime-6.8 | 6.8.1-1020.21~22.04.1 | — |
| Ubuntu Pro FIPS-updates 24.04 LTS | linux-fips | 6.8.0-78.78+fips1 | — |
| Ubuntu Pro FIPS-updates 22.04 LTS | linux-aws-fips | 5.15.0-1080.87+fips1 | USN-7387-2 |
| Ubuntu Pro FIPS-updates 22.04 LTS | linux-azure-fips | 5.15.0-1083.92+fips1 | USN-7387-2 |
| Ubuntu Pro FIPS-updates 22.04 LTS | linux-fips | 5.15.0-135.146+fips1 | USN-7387-2 |
| Ubuntu Pro FIPS-updates 22.04 LTS | linux-gcp-fips | 5.15.0-1079.88+fips1 | USN-7387-2 |
| Ubuntu Pro FIPS-preview 22.04 LTS | linux-fips +3 | No fix yet | — |
| Ubuntu Pro 20.04 LTS | linux-nvidia-tegra-5.15 | 5.15.0-1039.39~20.04.1 | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 9 | rv +77 | 5.14.0-570.12.1.el9_6 | RHSA-2025:6966 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP6 | kernel-64kb +6 | 6.4.0-150600.23.38.1 | SUSE-SU-2025:0499-1 |
| SLES 15 SP6 | kernel-azure +2 | 6.4.0-150600.8.26.1 | SUSE-SU-2025:0428-1 |
| SLES 15 SP6 | kernel-coco +3 | 6.4.0-15061.15.coco15sp6.1 | SUSE-SU-2025:0564-1 |
| SLES 15 SP6 | kernel-default-base | 6.4.0-150600.23.38.1.150600.12.16.2 | SUSE-SU-2025:0499-1 |
Show 4 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLE Micro 6.1 | kernel-default-base | 6.4.0-24.1.21.4 | SUSE-SU-2025:20248-1 |
| SLE Micro 6.1 | kernel-livepatch-MICRO-6-0-RT_Update_5 | 1-1.1 | SUSE-SU-2025:20249-1 |
| SLE Micro 6.1 | kernel-livepatch-MICRO-6-0_Update_5 | 1-1.2 | SUSE-SU-2025:20248-1 |
| SLE Micro 6.1 | kernel-rt +4 | 6.4.0-25.1 | SUSE-SU-2025:20249-1, SUSE-SU-2025:20248-1 |
| SLE Micro 6.0 | kernel-default-base | 6.4.0-24.1.21.4 | SUSE-SU-2025:20165-1 |
| SLE Micro 6.0 | kernel-livepatch-MICRO-6-0-RT_Update_5 | 1-1.1 | SUSE-SU-2025:20166-1 |
| SLE Micro 6.0 | kernel-livepatch-MICRO-6-0_Update_5 | 1-1.2 | SUSE-SU-2025:20165-1 |
| SLE Micro 6.0 | kernel-rt +4 | 6.4.0-25.1 | SUSE-SU-2025:20166-1, SUSE-SU-2025:20165-1 |
| SLE Live Patching 15 SP6 | kernel-default | 6.4.0-150600.23.38.1 | SUSE-SU-2025:0499-1 |
| SLE Live Patching 15 SP6 | kernel-livepatch-SLE15-SP6-RT_Update_8 | 1-150600.1.3.1 | SUSE-SU-2025:0557-1 |
| SLE Live Patching 15 SP6 | kernel-livepatch-SLE15-SP6_Update_8 | 1-150600.13.3.2 | SUSE-SU-2025:0499-1 |
| SUSE Real Time Module 15 SP6 | kernel-rt +3 | 6.4.0-150600.10.26.1 | SUSE-SU-2025:0557-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Leap 15.6 | dtb-aarch64 +10 | 6.4.0-150600.23.38.1 | SUSE-SU-2025:0499-1 |
| openSUSE Leap 15.6 | kernel-azure +2 | 6.4.0-150600.8.26.1 | SUSE-SU-2025:0428-1 |
| openSUSE Leap 15.6 | kernel-default-base | 6.4.0-150600.23.38.1.150600.12.16.2 | SUSE-SU-2025:0499-1 |
| openSUSE Leap 15.6 | kernel-rt +3 | 6.4.0-150600.10.26.1 | SUSE-SU-2025:0557-1 |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2023 | kernel-livepatch-6.1.124-134.200 | 1.0-0.amzn2023 | ALAS2023-2025-809 |
| Amazon Linux 2023 | perf +14 | 6.1.124-134.200.amzn2023 | ALAS2023-2025-809 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 9 | bpftool | 7.5.0-802.el9_6 | ELSA-2025-6966 |
| Oracle Linux 9 | kernel-uek +34 | 6.12.0-101.33.4.3.el10uek | ELSA-2025-20530, ELSA-2025-20480 |
| Oracle Linux 9 | rv +28 | 5.14.0-570.12.1.0.1.el9_6 | ELSA-2025-6966 |
| Oracle Linux 8 | bpftool +13 | 5.15.0-305.176.4.el9uek | ELSA-2025-20095 |
Advisories 38
- RHSA-2025:6966 Red Hat Security Advisory: kernel security update Red Hat Security Advisories (RHSA) · Nov 13, 2026
- WID-SEC-2024-3762 Linux Kernel: Mehrere Schwachstellen ermöglichen Denial of Service BSI CERT-Bund (WID) · Nov 10, 2026
- USN-7449-1 linux, linux-aws, linux-azure, linux-azure-6.8, linux-ibm, linux-lowlatency, linux-lowlatency-hwe-6.8, linux-nvidia, linux-nvidia-6.8, linux-nvidia-lowlatency, linux-oem-6.8, linux-oracle, linux-oracle-6.8 vulnerabilities Ubuntu Security Notices (USN) · Nov 3, 2026
- USN-7450-1 linux-gcp, linux-gke, linux-gkeop vulnerabilities Ubuntu Security Notices (USN) · Nov 3, 2026
- USN-7468-1 linux-azure-nvidia vulnerabilities Ubuntu Security Notices (USN) · Nov 3, 2026
- USN-7453-1 linux-realtime vulnerabilities Ubuntu Security Notices (USN) · Nov 3, 2026
- USN-7451-1 linux-aws-6.8 vulnerabilities Ubuntu Security Notices (USN) · Nov 3, 2026
- USN-7524-1 linux-raspi vulnerabilities Ubuntu Security Notices (USN) · Nov 3, 2026
- USN-7523-1 linux-raspi-realtime vulnerabilities Ubuntu Security Notices (USN) · Nov 3, 2026
- USN-7310-1 linux-oem-6.11 vulnerabilities Ubuntu Security Notices (USN) · Nov 3, 2026
- USN-7452-1 linux-gcp-6.8 vulnerabilities Ubuntu Security Notices (USN) · Nov 3, 2026
- USN-7449-2 linux-hwe-6.8 vulnerabilities Ubuntu Security Notices (USN) · Nov 3, 2026
- USN-7459-1 linux-intel-iotg-5.15 vulnerabilities Ubuntu Security Notices (USN) · Oct 30, 2026
- USN-7459-2 linux-gcp-5.15 vulnerabilities Ubuntu Security Notices (USN) · Oct 30, 2026
- USN-7387-1 linux, linux-aws, linux-azure, linux-gcp, linux-gke, linux-gkeop, linux-ibm, linux-intel-iotg, linux-lowlatency, linux-lowlatency-hwe-5.15, linux-nvidia, linux-oracle, linux-oracle-5.15, linux-raspi vulnerabilities Ubuntu Security Notices (USN) · Oct 29, 2026
- USN-7387-2 linux-fips, linux-aws-fips, linux-azure-fips, linux-gcp-fips vulnerabilities Ubuntu Security Notices (USN) · Oct 29, 2026
- USN-7458-1 linux-ibm-5.15 vulnerabilities Ubuntu Security Notices (USN) · Oct 29, 2026
- USN-7387-3 linux-realtime, linux-intel-iot-realtime vulnerabilities Ubuntu Security Notices (USN) · Oct 29, 2026
- USN-7388-1 linux-aws-5.15, linux-kvm vulnerabilities Ubuntu Security Notices (USN) · Oct 29, 2026
- USN-7421-1 linux-azure-5.15, linux-azure-fde-5.15 vulnerabilities Ubuntu Security Notices (USN) · Oct 29, 2026
- USN-7389-1 linux-nvidia-tegra, linux-nvidia-tegra-igx vulnerabilities Ubuntu Security Notices (USN) · Oct 29, 2026
- USN-7390-1 linux-xilinx-zynqmp vulnerabilities Ubuntu Security Notices (USN) · Oct 29, 2026
- USN-7407-1 linux-hwe-5.15 vulnerabilities Ubuntu Security Notices (USN) · Oct 29, 2026
- WID-SEC-2025-2855 IBM DataPower Gateway: Mehrere Schwachstellen BSI CERT-Bund (WID) · Sep 17, 2026
- SUSE-SU-2025:20165-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2025:20166-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2025:20248-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2025:20249-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Mar 23, 2026
- DLA-4076-1 linux-6.1 - security update Debian Security (DSA / DLA) · Mar 9, 2026
- SUSE-SU-2025:0564-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2025:0557-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2025:0499-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2025:0428-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- ALAS2023-2025-809 Important: kernel security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Oct 2, 2025
- ELSA-2025-20530 Important: Unbreakable Enterprise kernel security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Aug 18, 2025
- ELSA-2025-20480 Important: Unbreakable Enterprise kernel security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Jul 17, 2025
- ELSA-2025-6966 Moderate: kernel security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · May 16, 2025
- ELSA-2025-20095 Important: Unbreakable Enterprise kernel security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Feb 9, 2025
References
- https://git.kernel.org/stable/c/41219c147df8bbd6591f59af5d695fb6c9a1cbff
- https://git.kernel.org/stable/c/259bf925583ec9e3781df778cadf00594095090d
- https://git.kernel.org/stable/c/410896624db639500f24f46478b4bfa05c76bf56
- https://git.kernel.org/stable/c/c0c2744cd2939ec5999c51dbaf2af16886548b7b
- https://git.kernel.org/stable/c/63dfd728b30f79495dacc886127695a379805152
- https://git.kernel.org/stable/c/826cc42adf44930a633d11a5993676d85ddb0842