Description
In the Linux kernel, the following vulnerability has been resolved:
netfs: Fix kernel async DIO
Netfslib needs to be able to handle kernel-initiated asynchronous DIO that
is supplied with a bio_vec[] array. Currently, because of the async flag,
this gets passed to netfs_extract_user_iter() which throws a warning and
fails because it only handles IOVEC and UBUF iterators. This can be
triggered through a combination of cifs and a loopback blockdev with
something like:
mount //my/cifs/share /foo
dd if=/dev/zero of=/foo/m0 bs=4K count=1K
losetup --sector-size 4096 --direct-io=on /dev/loop2046 /foo/m0
echo hello >/dev/loop2046
This causes the following to appear in syslog:
WARNING: CPU: 2 PID: 109 at fs/netfs/iterator.c:50 netfs_extract_user_iter+0x170/0x250 [netfs]
and the write to fail.
Fix this by removing the check in netfs_unbuffered_write_iter_locked() that
causes async kernel DIO writes to be handled as userspace writes. Note
that this change relies on the kernel caller maintaining the existence of
the bio_vec array (or kvec[] or folio_queue) until the op is complete.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Linux | Linux | 6.8 | 6.12.10 |
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 | 6.12.10-1 | — |
| Debian 13 | linux | 6.12.10-1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 24.04 LTS | linux | 6.8.0-60.63 | USN-7513-1 |
| Ubuntu 24.04 LTS | linux-aws | 6.8.0-1029.31 | USN-7513-1 |
| Ubuntu 24.04 LTS | linux-azure | 6.8.0-1029.34 | USN-7513-3 |
| Ubuntu 24.04 LTS | linux-azure-6.11 | 6.11.0-1012.12~24.04.1 | — |
| Ubuntu 24.04 LTS | linux-azure-nvidia | 6.8.0-1016.17 | USN-7522-1 |
| Ubuntu 24.04 LTS | linux-gcp | 6.8.0-1030.32 | USN-7515-2 |
| Ubuntu 24.04 LTS | linux-gcp-6.11 | 6.11.0-1011.11~24.04.1 | — |
| Ubuntu 24.04 LTS | linux-gke | 6.8.0-1025.29 | USN-7515-1 |
| Ubuntu 24.04 LTS | linux-gkeop | 6.8.0-1012.14 | USN-7515-2 |
| Ubuntu 24.04 LTS | linux-hwe-6.11 | 6.11.0-21.21~24.04.1 | USN-7379-1 |
| Ubuntu 24.04 LTS | linux-ibm | 6.8.0-1026.26 | USN-7513-1 |
| Ubuntu 24.04 LTS | linux-lowlatency-hwe-6.11 | 6.11.0-1011.12~24.04.1 | USN-7381-1 |
| Ubuntu 24.04 LTS | linux-nvidia | 6.8.0-1028.31 | USN-7514-1 |
| Ubuntu 24.04 LTS | linux-nvidia-6.11 | 6.11.0-1007.7 | — |
| Ubuntu 24.04 LTS | linux-nvidia-lowlatency | 6.8.0-1028.31.1 | USN-7514-1 |
| Ubuntu 24.04 LTS | linux-nvidia-tegra | 6.8.0-1008.8 | — |
| Ubuntu 24.04 LTS | linux-oem-6.11 | 6.11.0-1017.17 | USN-7382-1 |
| Ubuntu 24.04 LTS | linux-oem-6.8 | 6.8.0-1028.28 | USN-7513-3 |
| Ubuntu 24.04 LTS | linux-oracle | 6.8.0-1026.27 | USN-7513-1 |
| 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 | 6.8.0-60.63.1 | USN-7513-1 |
| Ubuntu 24.04 LTS | linux-xilinx | 6.8.0-1017.18 | — |
| Ubuntu 22.04 LTS | linux-aws-6.8 | 6.8.0-1029.31~22.04.1 | USN-7513-1 |
| Ubuntu 22.04 LTS | linux-azure-6.8 | 6.8.0-1029.34~22.04.1 | USN-7513-3 |
| Ubuntu 22.04 LTS | linux-gcp-6.8 | 6.8.0-1030.32~22.04.1 | USN-7515-2 |
| Ubuntu 22.04 LTS | linux-hwe-6.8 | 6.8.0-60.63~22.04.1 | USN-7513-4 |
| Ubuntu 22.04 LTS | linux-ibm-6.8 | 6.8.0-1026.26~22.04.1 | — |
| Ubuntu 22.04 LTS | linux-lowlatency-hwe-6.8 | 6.8.0-60.63.1~22.04.1 | USN-7513-1 |
| Ubuntu 22.04 LTS | linux-nvidia-6.8 | 6.8.0-1028.31~22.04.1 | USN-7514-1 |
| Ubuntu 22.04 LTS | linux-oracle-6.8 | 6.8.0-1026.27~22.04.1 | USN-7513-5 |
| Ubuntu 22.04 LTS | linux-riscv +32 | No fix yet | — |
| Ubuntu 22.04 LTS | linux-riscv-6.8 | 6.8.0-62.65~22.04.1 | — |
| Ubuntu 20.04 LTS | linux-gke +28 | No fix yet | — |
| Ubuntu 18.04 LTS | linux-gcp +14 | No fix yet | — |
| Ubuntu 16.04 LTS | linux-hwe-edge | No fix yet | — |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| 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 | 6.8.1-1022.23 | USN-7513-2 |
| Ubuntu Pro Realtime 22.04 LTS | linux-realtime-6.8 | 6.8.1-1022.23~22.04.1 | — |
| Ubuntu Pro FIPS-updates 24.04 LTS | linux-fips | 6.8.0-78.78+fips1 | — |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 9 | kernel-uek +34 | 6.12.0-101.33.4.3.el10uek | ELSA-2025-20530, ELSA-2025-20480 |
Advisories 17
- WID-SEC-2025-0119 Linux Kernel: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 9, 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-7522-1 linux-azure-nvidia vulnerabilities Ubuntu Security Notices (USN) · Oct 30, 2026
- USN-7513-1 linux, linux-aws, linux-aws-6.8, linux-ibm, linux-lowlatency, linux-lowlatency-hwe-6.8, linux-oracle vulnerabilities Ubuntu Security Notices (USN) · Oct 30, 2026
- USN-7513-2 linux-realtime vulnerabilities Ubuntu Security Notices (USN) · Oct 30, 2026
- USN-7513-3 linux-azure, linux-azure-6.8, linux-oem-6.8 vulnerabilities Ubuntu Security Notices (USN) · Oct 30, 2026
- USN-7515-2 linux-gcp, linux-gcp-6.8, linux-gkeop vulnerabilities Ubuntu Security Notices (USN) · Oct 30, 2026
- USN-7514-1 linux-nvidia, linux-nvidia-6.8, linux-nvidia-lowlatency vulnerabilities Ubuntu Security Notices (USN) · Oct 30, 2026
- USN-7513-4 linux-hwe-6.8 vulnerabilities Ubuntu Security Notices (USN) · Oct 30, 2026
- USN-7513-5 linux-oracle-6.8 vulnerabilities Ubuntu Security Notices (USN) · Oct 30, 2026
- USN-7515-1 linux-gke vulnerabilities Ubuntu Security Notices (USN) · Oct 30, 2026
- USN-7379-1 linux, linux-aws, linux-azure, linux-gcp, linux-hwe-6.11, linux-oracle, linux-realtime vulnerabilities Ubuntu Security Notices (USN) · Oct 29, 2026
- USN-7382-1 linux-oem-6.11 vulnerabilities Ubuntu Security Notices (USN) · Oct 29, 2026
- USN-7381-1 linux-lowlatency-hwe-6.11 vulnerabilities Ubuntu Security Notices (USN) · Jun 3, 2026
- 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