Description
In the Linux kernel, the following vulnerability has been resolved:
nfsd: fix refcount leak in nfsd_set_fh_dentry()
nfsd exports a "pseudo root filesystem" which is used by NFSv4 to find
the various exported filesystems using LOOKUP requests from a known root
filehandle. NFSv3 uses the MOUNT protocol to find those exported
filesystems and so is not given access to the pseudo root filesystem.
If a v3 (or v2) client uses a filehandle from that filesystem,
nfsd_set_fh_dentry() will report an error, but still stores the export
in "struct svc_fh" even though it also drops the reference (exp_put()).
This means that when fh_put() is called an extra reference will be dropped
which can lead to use-after-free and possible denial of service.
Normal NFS usage will not provide a pseudo-root filehandle to a v3
client. This bug can only be triggered by the client synthesising an
incorrect filehandle.
To fix this we move the assignments to the svc_fh later, after all
possible error cases have been detected.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Linux | Linux | 6.12 | 6.12.59 |
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 | 6.17.9-1 | — |
| Debian 13 | linux | 6.12.63-1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 25.10 | linux | 6.17.0-14.14 | USN-8029-1 |
| Ubuntu 25.10 | linux-aws +2 | 6.17.0-1007.7 | USN-8030-1, USN-8029-2 |
| Ubuntu 25.10 | linux-azure +1 | 6.17.0-1008.8 | USN-8029-3, USN-8029-1 |
| Ubuntu 25.10 | linux-azure-fde | No fix yet | — |
| Ubuntu 25.10 | linux-realtime | 6.17.0-1006.7 | USN-8029-1 |
| Ubuntu 25.10 | linux-riscv | 6.17.0-14.14.1 | — |
| Ubuntu 24.04 LTS | linux-aws-6.17 +1 | 6.17.0-1007.7~24.04.1 | — |
| Ubuntu 24.04 LTS | linux-gcp-6.17 | 6.17.0-1008.8~24.04.1 | — |
| Ubuntu 24.04 LTS | linux-nvidia-6.17 | 6.17.0-1008.8 | — |
| Ubuntu 24.04 LTS | linux-oem-6.17 | 6.17.0-1011.11 | USN-8048-1 |
| Ubuntu 24.04 LTS | linux-riscv +17 | No fix yet | — |
| Ubuntu 22.04 LTS | linux-riscv +32 | No fix yet | — |
| Ubuntu 20.04 LTS | linux-gke +28 | No fix yet | — |
| 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 24.04 LTS | linux-realtime-6.14 | No fix yet | — |
| Ubuntu Pro Realtime 24.04 LTS | linux-realtime-6.17 | 6.17.0-1006.7~24.04.1 | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 16.0 | kernel-64kb +8 | 6.12.0-160000.9.1 | SUSE-SU-2026:20220-1 |
| SLES for SAP 16.0 | kernel-default-base | 6.12.0-160000.9.1.160000.2.6 | SUSE-SU-2026:20220-1 |
| SLES for SAP 16.0 | kernel-livepatch-SLE16_Update_0 | 5-160000.4.3 | SUSE-SU-2026:20149-1 |
| SLES for SAP 16.0 | kernel-livepatch-SLE16_Update_1 | 3-160000.1.1 | SUSE-SU-2026:20202-1 |
| SLES for SAP 16.0 | kernel-livepatch-SLE16_Update_2 | 2-160000.1.1 | SUSE-SU-2026:20148-1 |
| SLES 16.0 | kernel-64kb +8 | 6.12.0-160000.9.1 | SUSE-SU-2026:20228-1, SUSE-SU-2026:20220-1 |
| SLES 16.0 | kernel-default-base | 6.12.0-160000.9.1.160000.2.6 | SUSE-SU-2026:20220-1 |
| SLES 16.0 | kernel-livepatch-SLE16_Update_0 | 5-160000.4.3 | SUSE-SU-2026:20149-1 |
| SLES 16.0 | kernel-livepatch-SLE16_Update_1 | 3-160000.1.1 | SUSE-SU-2026:20202-1 |
| SLES 16.0 | kernel-livepatch-SLE16_Update_2 | 2-160000.1.1 | SUSE-SU-2026:20148-1 |
| SLE Micro 6.2 | kernel-default-base | 6.12.0-160000.9.1.160000.2.6 | SUSE-SU-2026:20207-1 |
| SLE Micro 6.2 | kernel-livepatch-SLE16-RT_Update_0 | 4-160000.3.4 | SUSE-SU-2026:20164-1 |
| SLE Micro 6.2 | kernel-livepatch-SLE16_Update_0 | 5-160000.4.3 | SUSE-SU-2026:20169-1 |
| SLE Micro 6.2 | kernel-livepatch-SLE16_Update_1 +1 | 3-160000.1.1 | SUSE-SU-2026:20171-1, SUSE-SU-2026:20168-1 |
| SLE Micro 6.2 | kernel-livepatch-SLE16_Update_2 +1 | 2-160000.1.1 | SUSE-SU-2026:20165-1, SUSE-SU-2026:20163-1 |
| SLE Micro 6.2 | kernel-rt +5 | 6.12.0-160000.9.1 | SUSE-SU-2026:20564-1, SUSE-SU-2026:20207-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Leap 16.0 | kernel-default-base | 6.12.0-160000.9.1.160000.2.6 | openSUSE-SU-2026:20145-1 |
| openSUSE Leap 16.0 | kernel-rt +11 | 6.12.0-160000.9.1 | openSUSE-SU-2026:20145-1 |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2023 | kernel-livepatch-6.12.63-84.121 | 1:1.0-0.amzn2023 | ALAS2023-2026-1430 |
| Amazon Linux 2023 | perf6.12 +14 | 1:6.12.63-84.121.amzn2023 | ALAS2023-2026-1430 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 9 | kernel-uek +34 | 6.12.0-107.59.3.2.el10uek | ELSA-2026-50006 |
Advisories 22
- USN-8029-2 linux-aws, linux-oracle vulnerabilities Ubuntu Security Notices (USN) · Nov 3, 2026
- USN-8048-1 linux-oem-6.17 vulnerabilities Ubuntu Security Notices (USN) · Nov 3, 2026
- USN-8029-3 linux-azure vulnerabilities Ubuntu Security Notices (USN) · Nov 3, 2026
- USN-8030-1 linux-gcp vulnerabilities Ubuntu Security Notices (USN) · Nov 3, 2026
- USN-8029-1 linux, linux-raspi, linux-realtime vulnerabilities Ubuntu Security Notices (USN) · Nov 3, 2026
- WID-SEC-2025-2672 Linux Kernel: Mehrere Schwachstellen ermöglichen Denial of Service BSI CERT-Bund (WID) · Aug 30, 2026
- SUSE-SU-2026:20564-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Jul 9, 2026
- openSUSE-SU-2026:20145-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2026:20228-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2026:20207-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2026:20220-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2026:20202-1 Security update for the Linux Kernel (Live Patch 1 for SUSE Linux Enterprise 16) SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2026:20149-1 Security update for the Linux Kernel (Live Patch 0 for SUSE Linux Enterprise 16) SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2026:20163-1 Security update for the Linux Kernel (Live Patch 2 for SUSE Linux Enterprise 16) SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2026:20164-1 Security update for the Linux Kernel RT (Live Patch 0 for SUSE Linux Enterprise 16) SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2026:20165-1 Security update for the Linux Kernel RT (Live Patch 2 for SUSE Linux Enterprise 16) SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2026:20168-1 Security update for the Linux Kernel RT (Live Patch 1 for SUSE Linux Enterprise 16) SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2026:20169-1 Security update for the Linux Kernel (Live Patch 0 for SUSE Linux Enterprise 16) SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2026:20171-1 Security update for the Linux Kernel (Live Patch 1 for SUSE Linux Enterprise 16) SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2026:20148-1 Security update for the Linux Kernel (Live Patch 2 for SUSE Linux Enterprise 16) SUSE / openSUSE Security Updates · Mar 23, 2026
- ALAS2023-2026-1430 Important: kernel6.12 security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Feb 18, 2026
- ELSA-2026-50006 Important: Unbreakable Enterprise kernel security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Jan 13, 2026