Description
In the Linux kernel, the following vulnerability has been resolved:
cifs: fix potential oops in cifs_oplock_break
With deferred close we can have closes that race with lease breaks,
and so with the current checks for whether to send the lease response,
oplock_response(), this can mean that an unmount (kill_sb) can occur
just before we were checking if the tcon->ses is valid. See below:
[Fri Aug 4 04:12:50 2023] RIP: 0010:cifs_oplock_break+0x1f7/0x5b0 [cifs]
[Fri Aug 4 04:12:50 2023] Code: 7d a8 48 8b 7d c0 c0 e9 02 48 89 45 b8 41 89 cf e8 3e f5 ff ff 4c 89 f7 41 83 e7 01 e8 82 b3 03 f2 49 8b 45 50 48 85 c0 74 5e <48> 83 78 60 00 74 57 45 84 ff 75 52 48 8b 43 98 48 83 eb 68 48 39
[Fri Aug 4 04:12:50 2023] RSP: 0018:ffffb30607ddbdf8 EFLAGS: 00010206
[Fri Aug 4 04:12:50 2023] RAX: 632d223d32612022 RBX: ffff97136944b1e0 RCX: 0000000080100009
[Fri Aug 4 04:12:50 2023] RDX: 0000000000000001 RSI: 0000000080100009 RDI: ffff97136944b188
[Fri Aug 4 04:12:50 2023] RBP: ffffb30607ddbe58 R08: 0000000000000001 R09: ffffffffc08e0900
[Fri Aug 4 04:12:50 2023] R10: 0000000000000001 R11: 000000000000000f R12: ffff97136944b138
[Fri Aug 4 04:12:50 2023] R13: ffff97149147c000 R14: ffff97136944b188 R15: 0000000000000000
[Fri Aug 4 04:12:50 2023] FS: 0000000000000000(0000) GS:ffff9714f7c00000(0000) knlGS:0000000000000000
[Fri Aug 4 04:12:50 2023] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[Fri Aug 4 04:12:50 2023] CR2: 00007fd8de9c7590 CR3: 000000011228e000 CR4: 0000000000350ef0
[Fri Aug 4 04:12:50 2023] Call Trace:
[Fri Aug 4 04:12:50 2023] <TASK>
[Fri Aug 4 04:12:50 2023] process_one_work+0x225/0x3d0
[Fri Aug 4 04:12:50 2023] worker_thread+0x4d/0x3e0
[Fri Aug 4 04:12:50 2023] ? process_one_work+0x3d0/0x3d0
[Fri Aug 4 04:12:50 2023] kthread+0x12a/0x150
[Fri Aug 4 04:12:50 2023] ? set_kthread_struct+0x50/0x50
[Fri Aug 4 04:12:50 2023] ret_from_fork+0x22/0x30
[Fri Aug 4 04:12:50 2023] </TASK>
To fix this change the ordering of the checks before sending the oplock_response
to first check if the openFileList is empty.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Linux | Linux | 6.3.13 – < 6.4, 5.15.121 – < 5.15.128, 6.1.39 – < 6.1.47, 6.4.4 – < 6.4.12 | 6.4 |
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 | 6.4.13-1 | — |
| Debian 13 | linux | 6.4.13-1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Nvidia-BlueField 22.04 LTS | linux-bluefield | 5.15.0-1033.35 | — |
| Ubuntu 24.04 LTS | linux-riscv +10 | No fix yet | — |
| Ubuntu 22.04 LTS | linux +1 | 5.15.0-91.101 | — |
| Ubuntu 22.04 LTS | linux-aws | 5.15.0-1051.56 | — |
| Ubuntu 22.04 LTS | linux-azure | 5.15.0-1051.59 | — |
| Ubuntu 22.04 LTS | linux-azure-fde | 5.15.0-1051.59.1 | — |
| Ubuntu 22.04 LTS | linux-gcp | 5.15.0-1048.56 | — |
| Ubuntu 22.04 LTS | linux-gke +1 | 5.15.0-1048.53 | — |
| Ubuntu 22.04 LTS | linux-gkeop | 5.15.0-1034.40 | — |
| Ubuntu 22.04 LTS | linux-ibm +1 | 5.15.0-1044.47 | — |
| Ubuntu 22.04 LTS | linux-intel-iotg | 5.15.0-1046.52 | — |
| Ubuntu 22.04 LTS | linux-nvidia | 5.15.0-1042.42 | — |
| Ubuntu 22.04 LTS | linux-nvidia-tegra | 5.15.0-1020.20 | — |
| Ubuntu 22.04 LTS | linux-nvidia-tegra-igx | 5.15.0-1007.7 | — |
| Ubuntu 22.04 LTS | linux-oracle | 5.15.0-1049.55 | — |
| Ubuntu 22.04 LTS | linux-riscv +32 | No fix yet | — |
| Ubuntu 22.04 LTS | linux-xilinx-zynqmp | 5.15.0-1027.31 | — |
| Ubuntu 20.04 LTS | linux-aws-5.15 | 5.15.0-1051.56~20.04.1 | — |
| Ubuntu 20.04 LTS | linux-azure-5.15 | 5.15.0-1051.59~20.04.1 | — |
| Ubuntu 20.04 LTS | linux-gcp-5.15 | 5.15.0-1048.56~20.04.1 | — |
| Ubuntu 20.04 LTS | linux-gke +28 | No fix yet | — |
| Ubuntu 20.04 LTS | linux-hwe-5.15 +1 | 5.15.0-91.101~20.04.1 | — |
| Ubuntu 20.04 LTS | linux-ibm-5.15 | 5.15.0-1044.47~20.04.1 | — |
| Ubuntu 20.04 LTS | linux-intel-iotg-5.15 | 5.15.0-1046.52~20.04.1 | — |
| Ubuntu 20.04 LTS | linux-nvidia-tegra-5.15 | 5.15.0-1020.20~20.04.1 | — |
| Ubuntu 20.04 LTS | linux-oracle-5.15 | 5.15.0-1049.55~20.04.1 | — |
| Ubuntu 20.04 LTS | linux-riscv-5.15 | 5.15.0-1047.51~20.04.1 | — |
| Ubuntu 18.04 LTS | linux-gcp +14 | No fix yet | — |
Show 2 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 22.04 LTS | linux-intel-iot-realtime | 5.15.0-1044.46 | — |
| Ubuntu Pro Realtime 22.04 LTS | linux-realtime | 5.15.0-1052.58 | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | kernel-64kb +6 | 6.4.0-150700.53.28.1 | SUSE-SU-2026:0315-1 |
| SLES 15 SP7 | kernel-azure +2 | 6.4.0-150700.20.24.1 | SUSE-SU-2026:0281-1 |
| SLES 15 SP7 | kernel-default-base | 6.4.0-150700.53.28.1.150700.17.19.1 | SUSE-SU-2026:0315-1 |
| SLES 15 SP6 | kernel-64kb +6 | 6.4.0-150600.23.84.1 | SUSE-SU-2026:0293-1 |
| SLES 15 SP6 | kernel-default-base | 6.4.0-150600.23.84.1.150600.12.38.1 | SUSE-SU-2026:0293-1 |
Show 6 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 15 SP6 | kernel-default-base | 6.4.0-150600.23.84.1.150600.12.38.1 | SUSE-SU-2026:0293-1 |
| SLES for SAP 15 SP6 | kernel-docs +4 | 6.4.0-150600.23.84.1 | SUSE-SU-2026:0293-1 |
| SLE Micro 6.1 | kernel-default-base | 6.4.0-39.1.21.16 | SUSE-SU-2026:20498-1 |
| SLE Micro 6.1 | kernel-rt +1 | 6.4.0-40.1 | SUSE-SU-2026:20876-1 |
| SLE Micro 6.1 | kernel-source +2 | 6.4.0-39.1 | SUSE-SU-2026:20498-1 |
| SLE Micro 6.0 | kernel-default-base | 6.4.0-39.1.21.16 | SUSE-SU-2026:20477-1 |
| SLE Micro 6.0 | kernel-rt +1 | 6.4.0-40.1 | SUSE-SU-2026:20845-1 |
| SLE Micro 6.0 | kernel-source +2 | 6.4.0-39.1 | SUSE-SU-2026:20477-1 |
| SLE Live Patching 15 SP7 | kernel-default | 6.4.0-150700.53.28.1 | SUSE-SU-2026:0315-1 |
| SLE Live Patching 15 SP7 | kernel-livepatch-SLE15-SP7-RT_Update_8 | 1-150700.1.3.1 | SUSE-SU-2026:0278-1 |
| SLE Live Patching 15 SP7 | kernel-livepatch-SLE15-SP7_Update_8 | 1-150700.15.3.1 | SUSE-SU-2026:0315-1 |
| SLE Live Patching 15 SP6 | kernel-default | 6.4.0-150600.23.84.1 | SUSE-SU-2026:0293-1 |
| SLE Live Patching 15 SP6 | kernel-livepatch-SLE15-SP6_Update_19 | 1-150600.13.3.1 | SUSE-SU-2026:0293-1 |
| SUSE Real Time Module 15 SP7 | kernel-rt +2 | 6.4.0-150700.7.28.1 | SUSE-SU-2026:0278-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Leap 15.6 | dtb-aarch64 +10 | 6.4.0-150600.23.84.1 | SUSE-SU-2026:0293-1 |
| openSUSE Leap 15.6 | kernel-default-base | 6.4.0-150600.23.84.1.150600.12.38.1 | SUSE-SU-2026:0293-1 |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2023 | kernel-livepatch-6.1.49-69.116 | 1.0-0.amzn2023 | ALAS2023-2023-330 |
| Amazon Linux 2023 | perf +12 | 6.1.49-69.116.amzn2023 | ALAS2023-2023-330 |
Advisories 10
- WID-SEC-2025-2941 Linux Kernel: Mehrere Schwachstellen ermöglichen Denial of Service BSI CERT-Bund (WID) · Nov 9, 2026
- SUSE-SU-2026:20876-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Mar 31, 2026
- SUSE-SU-2026:20845-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Mar 28, 2026
- SUSE-SU-2026:20498-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2026:20477-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2026:0293-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2026:0281-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2026:0278-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2026:0315-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Mar 23, 2026
- ALAS2023-2023-330 Important: kernel security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Feb 11, 2026