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9.8
CVE-2025-40212: Linux kernel NFS server can crash from crafted filehandle
CVE-2025-40212 · published 11 months ago
Summary
The NFS server component in the Linux kernel could mistakenly free memory it was still using when it receives a specially crafted request from an older NFS client. This could cause the server to stop working, potentially disrupting file sharing services. Updating to the latest kernel version provided by your Linux distribution resolves the issue.
What to do
- Update debian rootio-linux to version 6.12.63-1.root.io.64.
- Update canonical linux-aws-6.17 to version 6.17.0-1007.7~24.04.1.
- Update canonical linux-gcp-6.17 to version 6.17.0-1008.8~24.04.1.
- Update canonical linux-nvidia-6.17 to version 6.17.0-1008.8.
- Update canonical linux-oem-6.17 to version 6.17.0-1011.11.
- Update canonical linux-oracle-6.17 to version 6.17.0-1007.7~24.04.1.
- Update canonical linux-realtime-6.17 to version 6.17.0-1006.7~24.04.1.
- Update canonical linux to version 6.17.0-14.14.
- Update canonical linux-aws to version 6.17.0-1007.7.
- Update canonical linux-azure to version 6.17.0-1008.8.
- Update canonical linux-gcp to version 6.17.0-1007.7.
- Update canonical linux-oracle to version 6.17.0-1007.7.
- Update canonical linux-raspi to version 6.17.0-1008.8.
- Update canonical linux-realtime to version 6.17.0-1006.7.
- Update canonical linux-riscv to version 6.17.0-14.14.1.
- Update debian rootio-linux to version 6.12.95-1.root.io.150.
- Update linux to version 6.12.113-1.aikido.163.
- Update rootio-linux to version 6.12.113-1.aikido.163.
- Update debian linux to version 6.12.63-1.
- Update debian linux to version 6.17.9-1.
- Update linux kernel to version 6.17.9.
- Update linux linux to version b6bc86ce3944b10b9fc181fc00c1a520a20ed965 or later.
Affected software
| Ecosystem | Vendor | Product | Affected versions |
|---|---|---|---|
| Root:Debian:13 | debian | rootio-linux |
< 6.12.63-1.root.io.64 < 6.12.95-1.root.io.150 Fix: upgrade to 6.12.63-1.root.io.64
|
| – | linux | linux |
< b6bc86ce3944b10b9fc181fc00c1a520a20ed965 6.12 |
| Ubuntu:16.04:LTS | canonical | linux-hwe-edge | All versions |
| Ubuntu:18.04:LTS | canonical | linux-aws-5.0 | All versions |
| Ubuntu:18.04:LTS | canonical | linux-aws-5.3 | All versions |
| Ubuntu:18.04:LTS | canonical | linux-azure | All versions |
| Ubuntu:18.04:LTS | canonical | linux-azure-5.3 | All versions |
| Ubuntu:18.04:LTS | canonical | linux-azure-edge | All versions |
| Ubuntu:18.04:LTS | canonical | linux-gcp | All versions |
| Ubuntu:18.04:LTS | canonical | linux-gcp-5.3 | All versions |
| Ubuntu:18.04:LTS | canonical | linux-gke-4.15 | All versions |
| Ubuntu:18.04:LTS | canonical | linux-gke-5.4 | All versions |
| Ubuntu:18.04:LTS | canonical | linux-gkeop-5.4 | All versions |
| Ubuntu:18.04:LTS | canonical | linux-hwe | All versions |
| Ubuntu:18.04:LTS | canonical | linux-oem | All versions |
| Ubuntu:18.04:LTS | canonical | linux-oracle-5.0 | All versions |
| Ubuntu:18.04:LTS | canonical | linux-oracle-5.3 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-aws-5.11 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-aws-5.13 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-aws-5.8 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-azure-5.11 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-azure-5.13 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-azure-5.8 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-azure-fde | All versions |
| Ubuntu:20.04:LTS | canonical | linux-gcp-5.11 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-gcp-5.13 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-gcp-5.8 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-gke | All versions |
| Ubuntu:20.04:LTS | canonical | linux-gke-5.15 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-gkeop | All versions |
| Ubuntu:20.04:LTS | canonical | linux-gkeop-5.15 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-hwe-5.11 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-hwe-5.13 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-hwe-5.8 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-intel-5.13 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-oem-5.10 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-oem-5.13 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-oem-5.14 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-oem-5.6 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-oracle-5.11 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-oracle-5.13 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-oracle-5.8 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-raspi2 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-riscv | All versions |
| Ubuntu:20.04:LTS | canonical | linux-riscv-5.11 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-riscv-5.8 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-allwinner-5.19 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-aws-5.19 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-aws-6.2 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-aws-6.5 | All versions |
Showing 50 of 115. Show the rest
| Ecosystem | Vendor | Product | Affected versions |
|---|---|---|---|
| Ubuntu:22.04:LTS | canonical | linux-azure-5.19 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-azure-6.2 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-azure-6.5 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-azure-fde-5.19 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-azure-fde-6.2 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-gcp-5.19 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-gcp-6.2 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-gcp-6.5 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-hwe-5.19 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-hwe-6.2 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-hwe-6.5 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-intel-iot-realtime | All versions |
| Ubuntu:22.04:LTS | canonical | linux-lowlatency-hwe-5.19 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-lowlatency-hwe-6.2 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-lowlatency-hwe-6.5 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-nvidia-6.2 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-nvidia-6.5 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-oem-5.17 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-oem-6.0 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-oem-6.1 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-oem-6.5 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-oracle-6.5 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-realtime | All versions |
| Ubuntu:22.04:LTS | canonical | linux-riscv-5.19 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-riscv-6.5 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-starfive-5.19 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-starfive-6.2 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-starfive-6.5 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-aws-6.14 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-aws-6.17 |
< 6.17.0-1007.7~24.04.1 Fix: upgrade to 6.17.0-1007.7~24.04.1
|
| Ubuntu:24.04:LTS | canonical | linux-azure-6.11 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-azure-6.14 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-azure-fde-6.14 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-azure-nvidia-6.14 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-gcp-6.11 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-gcp-6.14 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-gcp-6.17 |
< 6.17.0-1008.8~24.04.1 Fix: upgrade to 6.17.0-1008.8~24.04.1
|
| Ubuntu:24.04:LTS | canonical | linux-hwe-6.11 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-hwe-6.14 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-lowlatency-hwe-6.11 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-nvidia-6.17 |
< 6.17.0-1008.8 Fix: upgrade to 6.17.0-1008.8
|
| Ubuntu:24.04:LTS | canonical | linux-oem-6.11 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-oem-6.14 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-oem-6.17 |
< 6.17.0-1011.11 Fix: upgrade to 6.17.0-1011.11
|
| Ubuntu:24.04:LTS | canonical | linux-oem-6.8 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-oracle-6.14 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-oracle-6.17 |
< 6.17.0-1007.7~24.04.1 Fix: upgrade to 6.17.0-1007.7~24.04.1
|
| Ubuntu:24.04:LTS | canonical | linux-raspi-realtime | All versions |
| Ubuntu:24.04:LTS | canonical | linux-riscv-6.14 | All versions |
| Ubuntu:Nvidia-BlueField:24.04:LTS | canonical | linux-bluefield | All versions |
| Ubuntu:Pro:Realtime:24.04:LTS | canonical | linux-realtime-6.14 | All versions |
| Ubuntu:Pro:Realtime:24.04:LTS | canonical | linux-realtime-6.17 |
< 6.17.0-1006.7~24.04.1 Fix: upgrade to 6.17.0-1006.7~24.04.1
|
| Ubuntu:25.10 | canonical | linux |
< 6.17.0-14.14 Fix: upgrade to 6.17.0-14.14
|
| Ubuntu:25.10 | canonical | linux-aws |
< 6.17.0-1007.7 Fix: upgrade to 6.17.0-1007.7
|
| Ubuntu:25.10 | canonical | linux-azure |
< 6.17.0-1008.8 Fix: upgrade to 6.17.0-1008.8
|
| Ubuntu:25.10 | canonical | linux-gcp |
< 6.17.0-1007.7 Fix: upgrade to 6.17.0-1007.7
|
| Ubuntu:25.10 | canonical | linux-oracle |
< 6.17.0-1007.7 Fix: upgrade to 6.17.0-1007.7
|
| Ubuntu:25.10 | canonical | linux-raspi |
< 6.17.0-1008.8 Fix: upgrade to 6.17.0-1008.8
|
| Ubuntu:25.10 | canonical | linux-realtime |
< 6.17.0-1006.7 Fix: upgrade to 6.17.0-1006.7
|
| Ubuntu:25.10 | canonical | linux-riscv |
< 6.17.0-14.14.1 Fix: upgrade to 6.17.0-14.14.1
|
| Root:Debian:13 | – | linux |
< 6.12.113-1.aikido.163 Fix: upgrade to 6.12.113-1.aikido.163
|
| Root:Debian:13 | – | rootio-linux |
< 6.12.113-1.aikido.163 Fix: upgrade to 6.12.113-1.aikido.163
|
| Debian:13 | debian | linux |
< 6.12.63-1 Fix: upgrade to 6.12.63-1
|
| Debian:14 | debian | linux |
< 6.17.9-1 Fix: upgrade to 6.17.9-1
|
| Linux | linux | kernel |
>= 6.13.0, < 6.17.9 Fix: upgrade to 6.17.9
|
Original advisory text
nfsd: fix refcount leak in nfsd_set_fh_dentry()
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.
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.
References
- https://ubuntu.com/security/CVE-2025-40212 Third Party Advisory
- https://www.cve.org/CVERecord?id=CVE-2025-40212 Third Party Advisory
- https://git.kernel.org/linus/8a7348a9ed70bda1c1f51d3f1815bcbdf9f3b38c Third Party Advisory
- https://ubuntu.com/security/notices/USN-8029-1 Vendor Advisory
- https://ubuntu.com/security/notices/USN-8030-1 Vendor Advisory
- https://ubuntu.com/security/notices/USN-8029-2 Vendor Advisory
- https://ubuntu.com/security/notices/USN-8048-1 Vendor Advisory
- https://ubuntu.com/security/notices/USN-8029-3 Vendor Advisory
- https://git.kernel.org/stable/c/8a7348a9ed70bda1c1f51d3f1815bcbdf9f3b38c URL
- https://git.kernel.org/stable/c/b6bc86ce3944b10b9fc181fc00c1a520a20ed965 URL
- https://git.kernel.org/stable/c/c83d7365cec5eb5ebeeee2a72e29b4ca58a7e4c2 URL
- https://security-tracker.debian.org/tracker/CVE-2025-40212 Vendor Advisory
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/40xxx/CVE-2025-40212... Vendor Advisory
- https://nvd.nist.gov/vuln/detail/CVE-2025-40212 Vendor Advisory
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git Product
Severity
9.8
Critical
Timeline
Published24 Nov 2025
Updated4 Nov 2026
First seen6 Mar 2026
Sources
CVE-2025-40212 · NVD
CVE-2025-40212 · MITRE
UBUNTU-CVE-2025-40212 · OSV
DEBIAN-CVE-2025-40212 · OSV
CVE-2025-40212 · OSV
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