Description
In the Linux kernel, the following vulnerability has been resolved:
smb: client: split cached_fid bitfields to avoid shared-byte RMW races
is_open, has_lease and on_list are stored in the same bitfield byte in
struct cached_fid but are updated in different code paths that may run
concurrently. Bitfield assignments generate byte read–modify–write
operations (e.g. `orb $mask, addr` on x86_64), so updating one flag can
restore stale values of the others.
A possible interleaving is:
CPU1: load old byte (has_lease=1, on_list=1)
CPU2: clear both flags (store 0)
CPU1: RMW store (old | IS_OPEN) -> reintroduces cleared bits
To avoid this class of races, convert these flags to separate bool
fields.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Linux | Linux | 6.1 | 6.1.164 |
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 | 6.18.12-1 | — |
| Debian 13 | linux | 6.12.73-1 | DSA-6141-1 |
| Debian 12 | linux | 6.1.164-1 | DSA-6163-1 |
| Debian 11 | linux-6.1 | 6.1.164-1~deb11u1 | DLA-4499-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Nvidia-BlueField 24.04 LTS | linux-bluefield | 6.8.0-1026.30 | — |
| Ubuntu 25.10 | linux +8 | No fix yet | — |
| Ubuntu 24.04 LTS | linux | 6.8.0-134.134 | USN-8492-1 |
| Ubuntu 24.04 LTS | linux-aws | 6.8.0-1060.63 | USN-8492-1 |
| Ubuntu 24.04 LTS | linux-azure | 6.8.0-1063.71 | USN-8606-1 |
| Ubuntu 24.04 LTS | linux-azure-fde | 6.8.0-1062.69 | USN-8607-1 |
| Ubuntu 24.04 LTS | linux-azure-nvidia | 6.8.0-1039.42 | — |
| Ubuntu 24.04 LTS | linux-gcp | 6.8.0-1063.69 | USN-8492-1 |
| Ubuntu 24.04 LTS | linux-gke | 6.8.0-1058.64 | USN-8492-2 |
| Ubuntu 24.04 LTS | linux-gkeop | 6.8.0-1045.48 | USN-8492-2 |
| Ubuntu 24.04 LTS | linux-ibm | 6.8.0-1060.61 | USN-8492-1 |
| Ubuntu 24.04 LTS | linux-lowlatency | 6.8.0-134.134.1 | USN-8497-1 |
| Ubuntu 24.04 LTS | linux-nvidia | 6.8.0-1058.61 | USN-8492-1 |
| Ubuntu 24.04 LTS | linux-nvidia-lowlatency | 6.8.0-1058.61.1 | USN-8492-2 |
| Ubuntu 24.04 LTS | linux-nvidia-tegra | 6.8.0-1029.30 | USN-8498-1 |
| Ubuntu 24.04 LTS | linux-oracle | 6.8.0-1057.58 | USN-8492-1 |
| Ubuntu 24.04 LTS | linux-raspi | 6.8.0-1060.64 | USN-8492-4 |
| Ubuntu 24.04 LTS | linux-riscv +26 | No fix yet | — |
| Ubuntu 24.04 LTS | linux-xilinx | 6.8.0-1032.33 | USN-8499-1 |
| Ubuntu 22.04 LTS | linux-aws-6.8 | 6.8.0-1060.63~22.04.1 | USN-8492-2 |
| Ubuntu 22.04 LTS | linux-azure +34 | No fix yet | — |
| Ubuntu 22.04 LTS | linux-azure-6.8 | 6.8.0-1063.71~22.04.1 | USN-8606-1 |
| Ubuntu 22.04 LTS | linux-azure-fde-6.8 | 6.8.0-1062.69~22.04.1 | USN-8609-1 |
| Ubuntu 22.04 LTS | linux-gcp-6.8 | 6.8.0-1063.69~22.04.1 | USN-8492-2 |
| Ubuntu 22.04 LTS | linux-hwe-6.8 | 6.8.0-136.136~22.04.1 | USN-8619-1 |
| Ubuntu 22.04 LTS | linux-ibm-6.8 | 6.8.0-1060.61~22.04.1 | USN-8492-2 |
| Ubuntu 22.04 LTS | linux-lowlatency-hwe-6.8 | 6.8.0-134.134.1~22.04.1 | USN-8497-1 |
| Ubuntu 22.04 LTS | linux-nvidia-6.8 | 6.8.0-1058.61~22.04.1 | USN-8492-1 |
| Ubuntu 22.04 LTS | linux-oracle-6.8 | 6.8.0-1057.58~22.04.1 | USN-8492-2 |
| Ubuntu 22.04 LTS | linux-riscv-6.8 | 6.8.0-134.134~22.04.1 | — |
| Ubuntu 20.04 LTS | linux-gke +28 | No fix yet | — |
Show 8 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 18.04 LTS | linux-gcp +14 | No fix yet | — |
| Ubuntu 16.04 LTS | linux-hwe-edge | No fix yet | — |
| Ubuntu Pro Realtime 24.04 LTS | linux-raspi-realtime | 6.8.0-2049.50 | USN-8492-3 |
| Ubuntu Pro Realtime 24.04 LTS | linux-realtime | 6.8.1-1055.56 | USN-8492-1 |
| Ubuntu Pro Realtime 24.04 LTS | linux-realtime-6.14 +1 | No fix yet | — |
| Ubuntu Pro Realtime 22.04 LTS | linux-realtime-6.8 | 6.8.1-1055.56~22.04.1 | USN-8492-1 |
| Ubuntu Pro FIPS-updates 24.04 LTS | linux-aws-fips | 6.8.0-1060.63+fips1 | USN-8492-1 |
| Ubuntu Pro FIPS-updates 24.04 LTS | linux-azure-fips | 6.8.0-1062.69+fips1 | USN-8492-5 |
| Ubuntu Pro FIPS-updates 24.04 LTS | linux-fips | 6.8.0-134.134+fips1 | USN-8492-5 |
| Ubuntu Pro FIPS-updates 24.04 LTS | linux-gcp-fips | 6.8.0-1063.69+fips1 | USN-8492-1 |
| Ubuntu Pro FIPS-updates 22.04 LTS | linux-azure-fips | No fix yet | — |
| Ubuntu Pro FIPS-preview 22.04 LTS | linux-azure-fips | No fix yet | — |
| Ubuntu Pro 20.04 LTS | linux-azure-5.15 +1 | No fix yet | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | kernel-64kb +7 | 6.4.0-150700.53.81.1 | SUSE-SU-2026:4254-1 |
| SLES 15 SP7 | kernel-default-base | 6.4.0-150700.53.81.1.150700.17.45.1 | SUSE-SU-2026:4254-1 |
| SLES 15 SP6 | kernel-64kb +6 | 6.4.0-150600.23.135.1 | SUSE-SU-2026:4369-1 |
| SLES 15 SP6 | kernel-default-base | 6.4.0-150600.23.135.1.150600.12.62.4 | SUSE-SU-2026:4369-1 |
Show 9 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 16.0 | kernel-64kb +8 | 6.12.0-160000.27.1 | SUSE-SU-2026:20931-1 |
| SLES for SAP 16.0 | kernel-default-base | 6.12.0-160000.27.1.160000.2.8 | SUSE-SU-2026:20931-1 |
| SLES for SAP 15 SP6 | kernel-default-base | 6.4.0-150600.23.135.1.150600.12.62.4 | SUSE-SU-2026:4369-1 |
| SLES for SAP 15 SP6 | kernel-docs +4 | 6.4.0-150600.23.135.1 | SUSE-SU-2026:4369-1 |
| SLES 16.0 | kernel-64kb +8 | 6.12.0-160000.27.1 | SUSE-SU-2026:20931-1 |
| SLES 16.0 | kernel-default-base | 6.12.0-160000.27.1.160000.2.8 | SUSE-SU-2026:20931-1 |
| SLE Micro 6.2 | kernel-default-base | 6.12.0-160000.27.1.160000.2.8 | SUSE-SU-2026:20838-1 |
| SLE Micro 6.2 | kernel-rt +5 | 6.12.0-160000.27.1 | SUSE-SU-2026:20873-1, SUSE-SU-2026:20838-1 |
| SLE Micro 6.1 | kernel-default-base | 6.4.0-52.1.21.34 | SUSE-SU-2026:23529-1 |
| SLE Micro 6.1 | kernel-rt +4 | 6.4.0-52.1 | SUSE-SU-2026:23529-1, SUSE-SU-2026:23528-1 |
| SLE Micro 6.0 | kernel-default-base | 6.4.0-52.1.21.36 | SUSE-SU-2026:23481-1 |
| SLE Micro 6.0 | kernel-rt +4 | 6.4.0-52.1 | SUSE-SU-2026:23481-1, SUSE-SU-2026:23477-1 |
| SLE Live Patching 15 SP7 | kernel-default | 6.4.0-150700.53.81.1 | SUSE-SU-2026:4254-1 |
| SLE Live Patching 15 SP7 | kernel-livepatch-SLE15-SP7-RT_Update_20 | 1-150700.1.3.1 | SUSE-SU-2026:4120-1 |
| SLE Live Patching 15 SP7 | kernel-livepatch-SLE15-SP7_Update_21 | 1-150700.15.3.1 | SUSE-SU-2026:4254-1 |
| SLE Live Patching 15 SP6 | kernel-default | 6.4.0-150600.23.135.1 | SUSE-SU-2026:4369-1 |
| SLE Live Patching 15 SP6 | kernel-livepatch-SLE15-SP6_Update_31 | 1-150600.13.3.4 | SUSE-SU-2026:4369-1 |
| SUSE Real Time Module 15 SP7 | kernel-rt +2 | 6.4.0-150700.7.75.1 | SUSE-SU-2026:4120-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | kernel-source | 6.19.8-1.1 | openSUSE-SU-2026:10387-1 |
| openSUSE Leap 16.0 | kernel-default-base | 6.12.0-160000.27.1.160000.2.8 | openSUSE-SU-2026:20416-1 |
| openSUSE Leap 16.0 | kernel-rt +11 | 6.12.0-160000.27.1 | openSUSE-SU-2026:20416-1 |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2023 | kernel-livepatch-6.12.73-95.123 +1 | 1:1.0-0.amzn2023 | ALAS2023-2026-1491, ALAS2023-2026-1487 |
| Amazon Linux 2023 | perf +14 | 1:6.1.164-196.303.amzn2023 | ALAS2023-2026-1491 |
| Amazon Linux 2023 | perf6.12 +14 | 1:6.12.73-95.123.amzn2023 | ALAS2023-2026-1487 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 9 | kernel-uek +34 | 6.12.0-200.74.27.el10uek | ELSA-2026-50372, ELSA-2026-50232, ELSA-2026-50160 |
Advisories 35
- USN-8607-1 linux-azure-fde vulnerabilities Ubuntu Security Notices (USN) · Nov 13, 2026
- USN-8609-1 linux-azure-fde-6.8 vulnerabilities Ubuntu Security Notices (USN) · Nov 13, 2026
- USN-8619-1 linux-hwe-6.8 vulnerabilities Ubuntu Security Notices (USN) · Nov 13, 2026
- USN-8606-1 linux-azure, linux-azure-6.8 vulnerabilities Ubuntu Security Notices (USN) · Nov 13, 2026
- WID-SEC-2026-0462 Linux Kernel: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 12, 2026
- USN-8497-1 linux-lowlatency, linux-lowlatency-hwe-6.8 vulnerabilities Ubuntu Security Notices (USN) · Nov 7, 2026
- USN-8499-1 linux-xilinx vulnerabilities Ubuntu Security Notices (USN) · Nov 7, 2026
- USN-8492-1 linux, linux-aws, linux-aws-fips, linux-gcp, linux-gcp-fips, linux-ibm, linux-nvidia, linux-nvidia-6.8, linux-oracle, linux-realtime, linux-realtime-6.8 vulnerabilities Ubuntu Security Notices (USN) · Nov 6, 2026
- USN-8492-2 linux-aws-6.8, linux-gcp-6.8, linux-gke, linux-gkeop, linux-ibm-6.8, linux-nvidia-lowlatency, linux-oracle-6.8 vulnerabilities Ubuntu Security Notices (USN) · Nov 6, 2026
- USN-8498-1 linux-nvidia-tegra vulnerabilities Ubuntu Security Notices (USN) · Nov 6, 2026
- USN-8492-3 linux-raspi-realtime vulnerabilities Ubuntu Security Notices (USN) · Nov 6, 2026
- USN-8492-5 linux-azure-fips, linux-fips vulnerabilities Ubuntu Security Notices (USN) · Nov 6, 2026
- USN-8492-4 linux-raspi vulnerabilities Ubuntu Security Notices (USN) · Nov 6, 2026
- SUSE-SU-2026:4254-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Oct 8, 2026
- SUSE-SU-2026:4369-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Oct 2, 2026
- SUSE-SU-2026:23528-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Sep 15, 2026
- SUSE-SU-2026:23529-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Sep 15, 2026
- SUSE-SU-2026:23477-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Sep 14, 2026
- SUSE-SU-2026:4120-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Sep 14, 2026
- SUSE-SU-2026:23481-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Sep 14, 2026
- SUSE-SU-2026:20873-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Jul 9, 2026
- ICSA-26-188-05 Siemens SINEC OS CISA ICS & IT advisories · Jul 7, 2026
- ELSA-2026-50372 Important: Unbreakable Enterprise kernel security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Jul 2, 2026
- ALAS2023-2026-1491 Important: kernel security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Jul 1, 2026
- SSA-253495 SSA-253495: Multiple Vulnerabilities in SINEC OS before V4.0 Siemens ProductCERT · Jun 2, 2026
- ALAS2023-2026-1487 Important: kernel6.12 security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · May 9, 2026
- ELSA-2026-50232 Important: Unbreakable Enterprise kernel security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Apr 15, 2026
- SUSE-SU-2026:20931-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Apr 2, 2026
- openSUSE-SU-2026:20416-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Mar 29, 2026
- SUSE-SU-2026:20838-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Mar 28, 2026
- DSA-6163-1 linux - security update Debian Security (DSA / DLA) · Mar 23, 2026
- DLA-4499-1 linux-6.1 - security update Debian Security (DSA / DLA) · Mar 23, 2026
- ELSA-2026-50160 Important: Unbreakable Enterprise kernel security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Mar 20, 2026
- openSUSE-SU-2026:10387-1 kernel-devel-6.19.8-1.1 on GA media SUSE / openSUSE Security Updates · Mar 19, 2026
- DSA-6141-1 linux - security update Debian Security (DSA / DLA) · Mar 9, 2026
References
- https://git.kernel.org/stable/c/569fecc56bfe4df66f05734d67daef887746656b
- https://git.kernel.org/stable/c/4386f6af8aaedd0c5ad6f659b40cadcc8f423828
- https://git.kernel.org/stable/c/3eaa22d688311c708b73f3c68bc6d0c8e3f0f77a
- https://git.kernel.org/stable/c/c4b9edd55987384a1f201d3d07ff71e448d79c1b
- https://git.kernel.org/stable/c/4cfa4c37dcbcfd70866e856200ed8a2894cac578
- https://git.kernel.org/stable/c/ec306600d5ba7148c9dbf8f5a8f1f5c1a044a241