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6.8
CVE-2021-47559: Linux kernel may crash due to null pointer in smc_vlan_by_tcpsk
CVE-2021-47559 · published 2 years ago
Summary
The Linux kernel packages for Ubuntu HWE and AWS/Azure cloud images contain code that can try to use a device reference that might be missing, which can cause the system to stop responding. This issue is fixed in the latest kernel updates. Apply the most recent kernel update for your Ubuntu release to eliminate the risk.
What to do
- Update debian linux to version 5.15.15-1.
- Update linux linux to version c94cbd262b6aa3b54d73a1ed1f9c0d19df57f4ff or later.
Affected software
| Ecosystem | Vendor | Product | Affected versions |
|---|---|---|---|
| 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:Pro:18.04:LTS | canonical | linux-aws-5.4 | All versions |
| Ubuntu:18.04:LTS | canonical | linux-azure | 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:18.04:LTS | canonical | linux-gcp | 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:18.04:LTS | canonical | linux-hwe | All versions |
| Ubuntu:Pro:18.04:LTS | canonical | linux-hwe-5.4 | All versions |
| Ubuntu:18.04:LTS | canonical | linux-hwe-edge | 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:20.04:LTS | canonical | linux | All versions |
| Ubuntu:Pro:20.04:LTS | canonical | linux-aws | 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:Pro:20.04:LTS | canonical | linux-azure | 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:Pro:20.04:LTS | canonical | linux-bluefield | All versions |
| Ubuntu:Pro:20.04:LTS | canonical | linux-gcp | 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-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:Pro:20.04:LTS | canonical | linux-ibm | All versions |
| Ubuntu:20.04:LTS | canonical | linux-intel-5.13 | All versions |
| Ubuntu:Pro:20.04:LTS | canonical | linux-iot | All versions |
| Ubuntu:Pro:20.04:LTS | canonical | linux-kvm | All versions |
| Ubuntu:20.04:LTS | canonical | linux-oem-5.10 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-oem-5.13 | All versions |
Showing 50 of 97. Show the rest
| Ecosystem | Vendor | Product | Affected versions |
|---|---|---|---|
| Ubuntu:20.04:LTS | canonical | linux-oem-5.14 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-oem-5.6 | All versions |
| Ubuntu:Pro:20.04:LTS | canonical | linux-oracle | 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: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:20.04:LTS | canonical | linux-riscv-5.8 | All versions |
| Ubuntu:Pro:20.04:LTS | canonical | linux-xilinx-zynqmp | All versions |
| Ubuntu:Pro:FIPS-updates:20.04:LTS | canonical | linux-aws-fips | All versions |
| Ubuntu:Pro:FIPS-updates:20.04:LTS | canonical | linux-azure-fips | All versions |
| Ubuntu:Pro:FIPS-updates:20.04:LTS | canonical | linux-fips | All versions |
| Ubuntu:Pro:FIPS-updates:20.04:LTS | canonical | linux-gcp-fips | All versions |
| Ubuntu:Pro:FIPS:20.04:LTS | canonical | linux-aws-fips | All versions |
| Ubuntu:Pro:FIPS:20.04:LTS | canonical | linux-azure-fips | All versions |
| Ubuntu:Pro:FIPS:20.04:LTS | canonical | linux-fips | All versions |
| Ubuntu:Pro:FIPS:20.04:LTS | canonical | linux-gcp-fips | 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-azure-5.19 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-azure-6.2 | 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-hwe-5.19 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-hwe-6.2 | 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-nvidia-6.2 | 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-realtime | All versions |
| Ubuntu:22.04:LTS | canonical | linux-riscv | All versions |
| Ubuntu:22.04:LTS | canonical | linux-riscv-5.19 | 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:24.04:LTS | canonical | linux-raspi-realtime | All versions |
| – | linux | linux |
< c94cbd262b6aa3b54d73a1ed1f9c0d19df57f4ff 4.18 |
| – | linux | linux_kernel |
>= 4.18, < 5.10.83 >= 5.11, < 5.15.6 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| Debian:12 | debian | linux |
< 5.15.15-1 Fix: upgrade to 5.15.15-1
|
Original advisory text
In the Linux kernel, the following vulnerability has been resolved: net/smc: Fix NULL pointer dereferencing in smc_vlan_by_tcpsk() Coverity reports a possible NULL dereferencing problem: in smc_vla...
In the Linux kernel, the following vulnerability has been resolved: net/smc: Fix NULL pointer dereferencing in smc_vlan_by_tcpsk() Coverity reports a possible NULL dereferencing problem: in smc_vlan_by_tcpsk(): 6. returned_null: netdev_lower_get_next returns NULL (checked 29 out of 30 times). 7. var_assigned: Assigning: ndev = NULL return value from netdev_lower_get_next. 1623 ndev = (struct net_device *)netdev_lower_get_next(ndev, &lower); CID 1468509 (#1 of 1): Dereference null return value (NULL_RETURNS) 8. dereference: Dereferencing a pointer that might be NULL ndev when calling is_vlan_dev. 1624 if (is_vlan_dev(ndev)) { Remove the manual implementation and use netdev_walk_all_lower_dev() to iterate over the lower devices. While on it remove an obsolete function parameter comment.
References
- https://ubuntu.com/security/CVE-2021-47559 Third Party Advisory
- https://www.cve.org/CVERecord?id=CVE-2021-47559 Third Party Advisory
- https://git.kernel.org/linus/587acad41f1bc48e16f42bb2aca63bf323380be8 Third Party Advisory
- https://security-tracker.debian.org/tracker/CVE-2021-47559 Vendor Advisory
- https://git.kernel.org/stable/c/587acad41f1bc48e16f42bb2aca63bf323380be8 Third Party Advisory
- https://git.kernel.org/stable/c/bb851d0fb02547d03cd40106b5f2391c4fed6ed1 Third Party Advisory
- https://git.kernel.org/stable/c/c94cbd262b6aa3b54d73a1ed1f9c0d19df57f4ff Third Party Advisory
Internet-facing
60 days
Internal
At next upgrade
- Not known to be exploited
- Needs hands-on effort to exploit
- Gives an attacker partial control
Severity
6.8
Medium
Type
CWE-476NULL Pointer Dereference
Timeline
Published24 May 2024
Updated4 Nov 2026
First seen17 Mar 2026
Sources
UBUNTU-CVE-2021-47559 · OSV
CVE-2021-47559 · NVD
CVE-2021-47559 · MITRE
DEBIAN-CVE-2021-47559 · OSV
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