Track vulnerabilities like this one.
Sign up free to get alerted when software you use is affected.
9.1
CVE-2026-89630: Linux kernel SMB client may miss data offset safety check
CVE-2026-89630 · published 28 days ago
Summary
A recent change in the Linux kernel’s SMB client code stopped correctly limiting a data offset value, meaning malformed network messages could bypass a safety check. This could lead to unexpected behavior or crashes when the system processes certain SMB traffic. Apply the latest kernel updates that include the corrected code to protect your systems.
What to do
- Update debian linux to version 7.2.6-1.
- Update linux kernel to version 7.2.4.
- Update linux linux to version 5b16a1967a01ad4496a7206a87c3eb16f1df2b05 or later.
Affected software
| Ecosystem | Vendor | Product | Affected versions |
|---|---|---|---|
| Debian:14 | debian | linux |
< 7.2.6-1 Fix: upgrade to 7.2.6-1
|
| – | linux | linux |
< 5b16a1967a01ad4496a7206a87c3eb16f1df2b05 6.19 |
| Linux | linux | kernel |
>= 6.19.0, < 7.2.4 Fix: upgrade to 7.2.4
|
| Ubuntu:Pro:14.04:LTS | canonical | linux | All versions |
| Ubuntu:Pro:14.04:LTS | canonical | linux-aws | All versions |
| Ubuntu:Pro:14.04:LTS | canonical | linux-azure | All versions |
| Ubuntu:Pro:14.04:LTS | canonical | linux-lts-xenial | All versions |
| Ubuntu:Pro:16.04:LTS | canonical | linux-aws-hwe | All versions |
| Ubuntu:Pro:16.04:LTS | canonical | linux-gcp | All versions |
| Ubuntu:Pro:16.04:LTS | canonical | linux-hwe | All versions |
| Ubuntu:16.04:LTS | canonical | linux-hwe-edge | All versions |
| Ubuntu:Pro:16.04:LTS | canonical | linux-kvm | All versions |
| Ubuntu:Pro:16.04:LTS | canonical | linux-oracle | All versions |
| Ubuntu:Pro:FIPS:16.04:LTS | canonical | linux-fips | 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:Pro:18.04:LTS | canonical | linux-aws-5.4 | All versions |
| Ubuntu:Pro:18.04:LTS | canonical | linux-azure-4.15 | All versions |
| Ubuntu:18.04:LTS | canonical | linux-azure-5.3 | All versions |
| Ubuntu:Pro:18.04:LTS | canonical | linux-azure-5.4 | All versions |
| Ubuntu:18.04:LTS | canonical | linux-azure-edge | All versions |
| Ubuntu:Pro:18.04:LTS | canonical | linux-gcp-4.15 | All versions |
| Ubuntu:18.04:LTS | canonical | linux-gcp-5.3 | All versions |
| Ubuntu:Pro:18.04:LTS | canonical | linux-gcp-5.4 | 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:Pro:18.04:LTS | canonical | linux-hwe-5.4 | All versions |
| Ubuntu:Pro:18.04:LTS | canonical | linux-ibm-5.4 | 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:Pro:18.04:LTS | canonical | linux-oracle-5.4 | All versions |
| Ubuntu:Pro:18.04:LTS | canonical | linux-raspi-5.4 | All versions |
| Ubuntu:Pro:FIPS-updates:18.04:LTS | canonical | linux-aws-fips | All versions |
| Ubuntu:Pro:FIPS-updates:18.04:LTS | canonical | linux-azure-fips | All versions |
| Ubuntu:Pro:FIPS-updates:18.04:LTS | canonical | linux-gcp-fips | 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:Pro:20.04:LTS | canonical | linux-aws-5.15 | 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:Pro:20.04:LTS | canonical | linux-azure-5.15 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-azure-5.8 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-azure-fde | All versions |
| Ubuntu:Pro:20.04:LTS | canonical | linux-azure-fde-5.15 | All versions |
| Ubuntu:Pro:20.04:LTS | canonical | linux-bluefield | All versions |
| Ubuntu:20.04:LTS | canonical | linux-gcp-5.11 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-gcp-5.13 | All versions |
Showing 50 of 171. Show the rest
| Ecosystem | Vendor | Product | Affected versions |
|---|---|---|---|
| Ubuntu:Pro:20.04:LTS | canonical | linux-gcp-5.15 | 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:Pro:20.04:LTS | canonical | linux-hwe-5.15 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-hwe-5.8 | All versions |
| Ubuntu:Pro:20.04:LTS | canonical | linux-ibm | All versions |
| Ubuntu:Pro:20.04:LTS | canonical | linux-ibm-5.15 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-intel-5.13 | All versions |
| Ubuntu:Pro:20.04:LTS | canonical | linux-intel-iotg-5.15 | All versions |
| Ubuntu:Pro:20.04:LTS | canonical | linux-iot | All versions |
| Ubuntu:Pro:20.04:LTS | canonical | linux-lowlatency-hwe-5.15 | All versions |
| Ubuntu:Pro:20.04:LTS | canonical | linux-nvidia-tegra-5.15 | 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:Pro:20.04:LTS | canonical | linux-oracle-5.15 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-oracle-5.8 | All versions |
| Ubuntu:Pro:20.04:LTS | canonical | linux-raspi | 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:Pro:20.04:LTS | canonical | linux-riscv-5.15 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-riscv-5.8 | All versions |
| Ubuntu:Pro:20.04:LTS | canonical | linux-xilinx-zynqmp | 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 |
| Ubuntu:22.04:LTS | canonical | linux-aws-6.8 | All 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-6.8 | 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-azure-fde-6.8 | 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-gcp-6.8 | 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-hwe-6.8 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-ibm-6.8 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-intel-iot-realtime | All versions |
| Ubuntu:22.04:LTS | canonical | linux-intel-iotg | All versions |
| Ubuntu:22.04:LTS | canonical | linux-lowlatency | 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-lowlatency-hwe-6.8 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-nvidia | 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-nvidia-6.8 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-nvidia-tegra | All versions |
| Ubuntu:22.04:LTS | canonical | linux-nvidia-tegra-igx | 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-oracle-6.8 | 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-riscv-6.8 | 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:Pro:Realtime:22.04:LTS | canonical | linux-realtime-6.8 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-aws-6.14 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-aws-6.17 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-aws-7.0 | All versions |
| 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-6.17 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-azure-7.0 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-azure-fde-6.14 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-azure-fde-6.17 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-azure-fde-7.0 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-azure-nvidia | 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 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-gcp-7.0 | All versions |
| 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-hwe-6.17 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-hwe-7.0 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-lowlatency-hwe-6.11 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-nvidia-6.11 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-nvidia-6.17 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-nvidia-7.0 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-nvidia-lowlatency | All versions |
| 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 | All versions |
| 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 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-oracle-7.0 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-raspi-realtime | All versions |
| Ubuntu:24.04:LTS | canonical | linux-riscv-6.14 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-riscv-6.17 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-riscv-7.0 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-xilinx | 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 | All versions |
| Ubuntu:26.04:LTS | canonical | linux-nvidia-bos | All versions |
| Ubuntu:26.04:LTS | canonical | linux-oem-7.0 | All versions |
Original advisory text
smb: client: restore the data_offset bound in is_valid_oplock_break()
In the Linux kernel, the following vulnerability has been resolved:
smb: client: restore the data_offset bound in is_valid_oplock_break()
Commit 83bfbd0bb902 ("cifs: Remove the RFC1002 header from smb_hdr")
changed the quantity this bound is measured against. It used to be
srv->total_read minus the 4-byte RFC1002 preamble that total_read then
included, so it was the SMB message length. The same commit stopped
counting the preamble, and the mechanical substitution to
srv->total_read - srv->pdu_size left an expression that is identically
zero: standard_receive3() reads MID_HEADER_SIZE() bytes and then exactly
pdu_length - MID_HEADER_SIZE() more, adding both to total_read.
len is therefore 0, the subtraction below it wraps, and no __u32
DataOffset can exceed the result, so the check from commit 097f5863b1a0
("cifs: read overflow in is_valid_oplock_break()") no longer rejects
anything. Use total_read, which is now the message length on its own.
smb: client: restore the data_offset bound in is_valid_oplock_break()
Commit 83bfbd0bb902 ("cifs: Remove the RFC1002 header from smb_hdr")
changed the quantity this bound is measured against. It used to be
srv->total_read minus the 4-byte RFC1002 preamble that total_read then
included, so it was the SMB message length. The same commit stopped
counting the preamble, and the mechanical substitution to
srv->total_read - srv->pdu_size left an expression that is identically
zero: standard_receive3() reads MID_HEADER_SIZE() bytes and then exactly
pdu_length - MID_HEADER_SIZE() more, adding both to total_read.
len is therefore 0, the subtraction below it wraps, and no __u32
DataOffset can exceed the result, so the check from commit 097f5863b1a0
("cifs: read overflow in is_valid_oplock_break()") no longer rejects
anything. Use total_read, which is now the message length on its own.
References
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git Product
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89630... Vendor Advisory
- https://nvd.nist.gov/vuln/detail/CVE-2026-89630 Vendor Advisory
- https://security-tracker.debian.org/tracker/CVE-2026-89630 Vendor Advisory
- https://ubuntu.com/security/CVE-2026-89630 Third Party Advisory
- https://www.cve.org/CVERecord?id=CVE-2026-89630 Third Party Advisory
- https://git.kernel.org/linus/ba22f575de9deeae4ae0859ca4315a7698226237 Third Party Advisory
- https://docs.bell-sw.com/security/cves/CVE-2026-89630 Vendor Advisory
- https://git.kernel.org/stable/c/5b16a1967a01ad4496a7206a87c3eb16f1df2b05
- https://git.kernel.org/stable/c/ba22f575de9deeae4ae0859ca4315a7698226237
Severity
9.1
Critical
Timeline
Published11 Sep 2026
Updated9 Oct 2026
First seen11 Sep 2026
Sources
CVE-2026-89630 · NVD
CVE-2026-89630 · MITRE
DEBIAN-CVE-2026-89630 · OSV
CVE-2026-89630 · OSV
UBUNTU-CVE-2026-89630 · OSV
BELL-CVE-2026-89630 · OSV
Track software like this
Free during beta