Description
A flaw was found in the Linux kernel's implementation of string matching within a packet. A privileged user (with root or CAP_NET_ADMIN) when inserting iptables rules could insert a rule which can panic the system. Kernel before kernel 5.5-rc1 is affected.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| — | kernel | kernel 5.5-rc1 | — |
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 | 5.5.13-1 | — |
| Debian 13 | linux | 5.5.13-1 | — |
| Debian 12 | linux | 5.5.13-1 | — |
| Debian 10 | linux | 4.19.171-2 | DSA-4843-1 |
| Debian 9 | linux-4.19 | 4.19.171-2~deb9u1 | DLA-2557-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 24.04 LTS | linux-raspi-realtime | No fix yet | — |
| Ubuntu 22.04 LTS | linux-realtime +1 | No fix yet | — |
| Ubuntu 20.04 LTS | linux | 5.4.0-66.74 | USN-4750-1 |
| Ubuntu 20.04 LTS | linux-aws | 5.4.0-1038.40 | USN-4750-1 |
| Ubuntu 20.04 LTS | linux-azure | 5.4.0-1040.42 | USN-4750-1 |
| Ubuntu 20.04 LTS | linux-gcp | 5.4.0-1037.40 | USN-4750-1 |
| Ubuntu 20.04 LTS | linux-gke | 5.4.0-1036.38 | — |
| Ubuntu 20.04 LTS | linux-gkeop | 5.4.0-1010.11 | USN-4750-1 |
| Ubuntu 20.04 LTS | linux-kvm | 5.4.0-1033.34 | USN-4750-1 |
| Ubuntu 20.04 LTS | linux-oracle | 5.4.0-1038.41 | USN-4750-1 |
| Ubuntu 20.04 LTS | linux-raspi | 5.4.0-1029.32 | USN-4750-1 |
| Ubuntu 20.04 LTS | linux-riscv +1 | No fix yet | — |
| Ubuntu 18.04 LTS | linux-aws-5.4 | 5.4.0-1038.40~18.04.1 | USN-4750-1 |
| Ubuntu 18.04 LTS | linux-azure-5.4 | 5.4.0-1040.42~18.04.1 | USN-4750-1 |
| Ubuntu 18.04 LTS | linux-gcp +12 | No fix yet | — |
| Ubuntu 18.04 LTS | linux-gcp-5.4 | 5.4.0-1037.40~18.04.1 | USN-4750-1 |
| Ubuntu 18.04 LTS | linux-gke-5.4 | 5.4.0-1036.38~18.04.1 | USN-4750-1 |
| Ubuntu 18.04 LTS | linux-gkeop-5.4 | 5.4.0-1010.11~18.04.1 | USN-4750-1 |
| Ubuntu 18.04 LTS | linux-hwe-5.4 | 5.4.0-66.74~18.04.2 | USN-4750-1 |
| Ubuntu 18.04 LTS | linux-oracle-5.4 | 5.4.0-1038.41~18.04.1 | USN-4750-1 |
| Ubuntu 18.04 LTS | linux-raspi-5.4 | 5.4.0-1029.32~18.04.1 | USN-4750-1 |
| Ubuntu 16.04 LTS | linux-hwe-edge | No fix yet | — |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro FIPS 20.04 LTS | linux-aws-fips +2 | No fix yet | — |
| Ubuntu Pro FIPS-updates 20.04 LTS | linux-aws-fips | 5.4.0-1069.73+fips2 | — |
| Ubuntu Pro FIPS-updates 20.04 LTS | linux-azure-fips | 5.4.0-1073.76+fips1 | — |
| Ubuntu Pro FIPS-updates 20.04 LTS | linux-gcp-fips | 5.4.0-1067.71~20.04.1 | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP2 | kernel-azure +2 | 5.3.18-18.35.2 | SUSE-SU-2021:0347-1 |
| SLES 15 SP2 | kernel-default-base | 5.3.18-24.49.2.9.21.2 | SUSE-SU-2021:0354-1 |
| SLES 15 SP2 | kernel-docs | 5.3.18-24.49.3 | SUSE-SU-2021:0354-1 |
| SLES 15 SP2 | kernel-syms +4 | 5.3.18-24.49.2 | SUSE-SU-2021:0354-1 |
| SLES 15 SP1 | kernel-docs +5 | 4.12.14-197.83.1 | SUSE-SU-2021:0532-1 |
| SLES 12 SP5 | kernel-azure +2 | 4.12.14-16.44.1 | SUSE-SU-2021:0348-1 |
| SLES 12 SP5 | kernel-docs | 4.12.14-122.60.2 | SUSE-SU-2021:0353-1 |
| SLES 12 SP5 | kernel-syms +3 | 4.12.14-122.60.1 | SUSE-SU-2021:0353-1 |
Show 12 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 15 SP1 | kernel-docs +4 | 4.12.14-197.83.1 | SUSE-SU-2021:0532-1 |
| SLES for SAP 12 SP5 | kernel-azure +2 | 4.12.14-16.44.1 | SUSE-SU-2021:0348-1 |
| SLES for SAP 12 SP5 | kernel-syms +2 | 4.12.14-122.60.1 | SUSE-SU-2021:0353-1 |
| SLE Real Time 12 SP5 | kernel-rt +3 | 4.12.14-10.31.1 | SUSE-SU-2021:0433-1 |
| SLE Live Patching 15 SP2 | kernel-default | 5.3.18-24.49.2 | SUSE-SU-2021:0354-1 |
| SLE Live Patching 15 SP2 | kernel-livepatch-SLE15-SP2_Update_10 | 1-5.3.2 | SUSE-SU-2021:0354-1 |
| SLE Live Patching 15 SP1 | kernel-default | 4.12.14-197.83.1 | SUSE-SU-2021:0532-1 |
| SLE Live Patching 15 SP1 | kernel-livepatch-SLE15-SP1_Update_22 | 1-3.5.1 | SUSE-SU-2021:0532-1 |
| SLE Live Patching 12 SP5 | kernel-default | 4.12.14-122.60.1 | SUSE-SU-2021:0353-1 |
| SLE Live Patching 12 SP5 | kgraft-patch-SLE12-SP5_Update_15 | 1-8.3.1 | SUSE-SU-2021:0353-1 |
| SLE HPC 15 SP1 | kernel-docs +4 | 4.12.14-197.83.1 | SUSE-SU-2021:0532-1 |
| SUSE Real Time Module 15 SP2 | kernel-rt +3 | 5.3.18-25.1 | SUSE-SU-2021:0427-1 |
| SUSE Manager Server 4.0 | kernel-docs +5 | 4.12.14-197.83.1 | SUSE-SU-2021:0532-1 |
| SUSE Manager Retail Branch Server 4.0 | kernel-docs +4 | 4.12.14-197.83.1 | SUSE-SU-2021:0532-1 |
| SUSE Manager Proxy 4.0 | kernel-docs +4 | 4.12.14-197.83.1 | SUSE-SU-2021:0532-1 |
| SUSE Enterprise Storage 6 | kernel-docs +4 | 4.12.14-197.83.1 | SUSE-SU-2021:0532-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Leap 15.2 | kernel-default-base | 5.3.18-lp152.63.1.lp152.8.21.1 | openSUSE-SU-2021:0241-1 |
| openSUSE Leap 15.2 | kernel-docs +8 | 5.3.18-lp152.63.1 | openSUSE-SU-2021:0241-1 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 7 | kernel-uek +4 | 5.4.17-2036.103.3.el8uek | ELSA-2021-9037 |
| Oracle Linux 7 | kernel-uek-container +1 | 5.4.17-2036.103.3.el8 | ELSA-2021-9038 |
| Oracle Linux 7 | perf +3 | 5.4.17-2036.103.3.el7uek | ELSA-2021-9037 |
Advisories 13
- USN-4750-1 linux, linux-aws, linux-aws-5.4, linux-azure, linux-azure-5.4, linux-gcp, linux-gcp-5.4, linux-gke-5.4, linux-gkeop, linux-gkeop-5.4, linux-hwe-5.4, linux-kvm, linux-oracle, linux-oracle-5.4, linux-raspi, linux-raspi-5.4 vulnerabilities Ubuntu Security Notices (USN) · Jun 3, 2026
- DSA-4843-1 linux - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-2557-1 linux-4.19 - security update Debian Security (DSA / DLA) · Mar 9, 2026
- SUSE-SU-2021:0354-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:0532-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:0348-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:0427-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:0347-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2021:0241-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:0353-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:0433-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · May 2, 2025
- ELSA-2021-9038 Important: Unbreakable Enterprise kernel-container security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Feb 8, 2021
- ELSA-2021-9037 Important: Unbreakable Enterprise kernel security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Feb 8, 2021