Description
In the Linux kernel, the following vulnerability has been resolved:
l2tp: pass correct message length to ip6_append_data
l2tp_ip6_sendmsg needs to avoid accounting for the transport header
twice when splicing more data into an already partially-occupied skbuff.
To manage this, we check whether the skbuff contains data using
skb_queue_empty when deciding how much data to append using
ip6_append_data.
However, the code which performed the calculation was incorrect:
ulen = len + skb_queue_empty(&sk->sk_write_queue) ? transhdrlen : 0;
...due to C operator precedence, this ends up setting ulen to
transhdrlen for messages with a non-zero length, which results in
corrupted packets on the wire.
Add parentheses to correct the calculation in line with the original
intent.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Linux | Linux | 4.19.296 – < 4.19.308, 5.4.258 – < 5.4.270, 5.10.198 – < 5.10.211, 5.15.135 – < 5.15.150, 6.1.57 – < 6.1.80, 4.14.327 – < 4.15, 6.5.7 – < 6.6, 6.6 | 4.19.308 |
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 | 6.7.7-1 | — |
| Debian 13 | linux | 6.7.7-1 | — |
| Debian 12 | linux | 6.1.82-1 | — |
| Debian 11 | linux | 5.10.216-1 | DSA-5681-1 |
| Debian 10 | linux | 4.19.316-1 | DLA-3840-1 |
| Debian 10 | linux-5.10 | 5.10.216-1~deb10u1 | DLA-3842-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Nvidia-BlueField 22.04 LTS | linux-bluefield | 5.15.0-1044.46 | — |
| Ubuntu 22.04 LTS | linux | 5.15.0-112.122 | USN-6820-1 |
| Ubuntu 22.04 LTS | linux-aws | 5.15.0-1063.69 | USN-6821-3 |
| Ubuntu 22.04 LTS | linux-azure | 5.15.0-1066.75 | USN-6821-4 |
| Ubuntu 22.04 LTS | linux-azure-fde | 5.15.0-1067.76.1 | USN-6821-4 |
| Ubuntu 22.04 LTS | linux-gcp | 5.15.0-1062.70 | USN-6820-1 |
| Ubuntu 22.04 LTS | linux-gke | 5.15.0-1060.66 | USN-6821-1 |
| Ubuntu 22.04 LTS | linux-gkeop | 5.15.0-1046.53 | USN-6821-2 |
| Ubuntu 22.04 LTS | linux-ibm | 5.15.0-1056.59 | USN-6821-1 |
| Ubuntu 22.04 LTS | linux-intel-iotg | 5.15.0-1058.64 | USN-6821-1 |
| Ubuntu 22.04 LTS | linux-kvm | 5.15.0-1060.65 | USN-6821-2 |
| Ubuntu 22.04 LTS | linux-lowlatency | 5.15.0-110.120 | USN-6820-1 |
| Ubuntu 22.04 LTS | linux-nvidia | 5.15.0-1058.59 | USN-6820-2 |
| Ubuntu 22.04 LTS | linux-nvidia-tegra | 5.15.0-1026.26 | — |
| Ubuntu 22.04 LTS | linux-nvidia-tegra-igx | 5.15.0-1015.15 | — |
| Ubuntu 22.04 LTS | linux-oracle | 5.15.0-1061.67 | USN-6821-1 |
| Ubuntu 22.04 LTS | linux-raspi | 5.15.0-1058.61 | USN-6919-1 |
| Ubuntu 22.04 LTS | linux-riscv +31 | No fix yet | — |
| Ubuntu 22.04 LTS | linux-xilinx-zynqmp | 5.15.0-1030.34 | USN-6820-1 |
| Ubuntu 20.04 LTS | linux | 5.4.0-186.206 | USN-6831-1 |
| Ubuntu 20.04 LTS | linux-aws | 5.4.0-1126.136 | USN-6831-1 |
| Ubuntu 20.04 LTS | linux-aws-5.15 | 5.15.0-1063.69~20.04.1 | USN-6821-3 |
| Ubuntu 20.04 LTS | linux-azure | 5.4.0-1131.138 | USN-6831-1 |
| Ubuntu 20.04 LTS | linux-azure-5.15 | 5.15.0-1065.74~20.04.1 | — |
| Ubuntu 20.04 LTS | linux-bluefield | 5.4.0-1086.93 | USN-6867-1 |
| Ubuntu 20.04 LTS | linux-gcp | 5.4.0-1130.139 | USN-6831-1 |
| Ubuntu 20.04 LTS | linux-gcp-5.15 | 5.15.0-1062.70~20.04.1 | USN-6820-1 |
| Ubuntu 20.04 LTS | linux-gke +26 | No fix yet | — |
| Ubuntu 20.04 LTS | linux-gkeop | 5.4.0-1093.97 | USN-6831-1 |
| Ubuntu 20.04 LTS | linux-gkeop-5.15 | 5.15.0-1046.53~20.04.1 | USN-6821-2 |
| Ubuntu 20.04 LTS | linux-hwe-5.15 | 5.15.0-113.123~20.04.1 | USN-6871-1 |
| Ubuntu 20.04 LTS | linux-ibm | 5.4.0-1073.78 | USN-6831-1 |
| Ubuntu 20.04 LTS | linux-ibm-5.15 | 5.15.0-1057.60~20.04.1 | USN-6892-1 |
| Ubuntu 20.04 LTS | linux-intel-iotg-5.15 | 5.15.0-1058.64~20.04.1 | USN-6828-1 |
| Ubuntu 20.04 LTS | linux-iot | 5.4.0-1038.39 | USN-6867-1 |
| Ubuntu 20.04 LTS | linux-kvm | 5.4.0-1114.121 | USN-6831-1 |
| Ubuntu 20.04 LTS | linux-lowlatency-hwe-5.15 | 5.15.0-110.120~20.04.1 | USN-6820-1 |
| Ubuntu 20.04 LTS | linux-nvidia-tegra-5.15 | 5.15.0-1027.27~20.04.1 | — |
| Ubuntu 20.04 LTS | linux-oracle | 5.4.0-1125.134 | USN-6831-1 |
| Ubuntu 20.04 LTS | linux-oracle-5.15 | 5.15.0-1061.67~20.04.1 | — |
| Ubuntu 20.04 LTS | linux-raspi | 5.4.0-1110.122 | USN-6831-1 |
| Ubuntu 20.04 LTS | linux-riscv-5.15 | 5.15.0-1059.63~20.04.1 | — |
| Ubuntu 20.04 LTS | linux-xilinx-zynqmp | 5.4.0-1045.49 | USN-6831-1 |
| Ubuntu 18.04 LTS | linux-gcp +13 | No fix yet | — |
| Ubuntu 16.04 LTS | linux-hwe-edge | No fix yet | — |
Show 9 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro Realtime 24.04 LTS | linux-raspi-realtime | 6.8.0-2002.2 | — |
| Ubuntu Pro Realtime 22.04 LTS | linux-intel-iot-realtime | 5.15.0-1056.58 | — |
| Ubuntu Pro Realtime 22.04 LTS | linux-realtime | 5.15.0-1064.72 | — |
| Ubuntu Pro FIPS-updates 22.04 LTS | linux-aws-fips | 5.15.0-1063.69+fips1 | — |
| Ubuntu Pro FIPS-updates 22.04 LTS | linux-azure-fips | 5.15.0-1065.74+fips1 | — |
| Ubuntu Pro FIPS-updates 22.04 LTS | linux-fips | 5.15.0-111.121+fips1 | — |
| Ubuntu Pro FIPS-updates 22.04 LTS | linux-gcp-fips | 5.15.0-1062.70+fips1 | — |
| Ubuntu Pro FIPS-updates 20.04 LTS | linux-aws-fips | 5.4.0-1126.136+fips2 | — |
| Ubuntu Pro FIPS-updates 20.04 LTS | linux-azure-fips | 5.4.0-1131.138+fips1 | — |
| Ubuntu Pro FIPS-updates 20.04 LTS | linux-fips | 5.4.0-1100.110 | — |
| Ubuntu Pro FIPS-updates 20.04 LTS | linux-gcp-fips | 5.4.0-1130.139+fips1 | — |
| Ubuntu Pro FIPS-updates 18.04 LTS | linux-fips +3 | No fix yet | — |
| Ubuntu Pro FIPS-updates 16.04 LTS | linux-fips | No fix yet | — |
| Ubuntu Pro 18.04 LTS | linux +5 | No fix yet | — |
| Ubuntu Pro 18.04 LTS | linux-aws-5.4 | 5.4.0-1126.136~18.04.1 | USN-6831-1 |
| Ubuntu Pro 18.04 LTS | linux-azure-5.4 | 5.4.0-1131.138~18.04.1 | USN-6831-1 |
| Ubuntu Pro 18.04 LTS | linux-gcp-5.4 | 5.4.0-1130.139~18.04.1 | USN-6831-1 |
| Ubuntu Pro 18.04 LTS | linux-hwe-5.4 | 5.4.0-186.206~18.04.1 | USN-6831-1 |
| Ubuntu Pro 18.04 LTS | linux-ibm-5.4 | 5.4.0-1073.78~18.04.1 | USN-6831-1 |
| Ubuntu Pro 18.04 LTS | linux-oracle-5.4 | 5.4.0-1125.134~18.04.1 | USN-6831-1 |
| Ubuntu Pro 18.04 LTS | linux-raspi-5.4 | 5.4.0-1110.122~18.04.1 | USN-6831-1 |
| Ubuntu Pro 16.04 LTS | linux +7 | No fix yet | — |
| Ubuntu Pro 14.04 LTS | linux-aws +2 | No fix yet | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP5 | kernel-azure +2 | 4.12.14-16.188.1 | SUSE-SU-2024:1979-1 |
| SLES 12 SP5 | kernel-docs +4 | 4.12.14-122.219.1 | SUSE-SU-2024:2184-1 |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 12 SP5 | kernel-azure +2 | 4.12.14-16.188.1 | SUSE-SU-2024:1979-1 |
| SLES for SAP 12 SP5 | kernel-syms +2 | 4.12.14-122.219.1 | SUSE-SU-2024:2184-1 |
| SLE Real Time 12 SP5 | kernel-rt +3 | 4.12.14-10.188.1 | SUSE-SU-2024:1983-1 |
| SLE Live Patching 12 SP5 | kernel-default | 4.12.14-122.219.1 | SUSE-SU-2024:2184-1 |
| SLE Live Patching 12 SP5 | kgraft-patch-SLE12-SP5_Update_57 | 1-8.3.1 | SUSE-SU-2024:2184-1 |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2 | kernel-livepatch-4.14.343-259.562 | 1.0-0.amzn2 | ALAS2-2024-2549 |
| Amazon Linux 2 | perf +8 | 4.14.343-259.562.amzn2 | ALAS2-2024-2549 |
Advisories 24
- USN-6828-1 linux-intel-iotg-5.15 vulnerabilities Ubuntu Security Notices (USN) · Oct 29, 2026
- USN-6831-1 linux, linux-aws, linux-aws-5.4, linux-azure, linux-azure-5.4, linux-gcp, linux-gcp-5.4, linux-gkeop, linux-hwe-5.4, linux-ibm, linux-ibm-5.4, linux-kvm, linux-oracle, linux-oracle-5.4, linux-raspi, linux-raspi-5.4, linux-xilinx-zynqmp vulnerabilities Ubuntu Security Notices (USN) · Oct 27, 2026
- USN-6919-1 linux-raspi vulnerabilities Ubuntu Security Notices (USN) · Oct 27, 2026
- USN-6821-4 linux-azure, linux-azure-fde vulnerabilities Ubuntu Security Notices (USN) · Oct 27, 2026
- USN-6871-1 linux-hwe-5.15 vulnerabilities Ubuntu Security Notices (USN) · Oct 27, 2026
- USN-6867-1 linux-bluefield, linux-iot vulnerabilities Ubuntu Security Notices (USN) · Oct 27, 2026
- USN-6821-1 linux-gke, linux-ibm, linux-intel-iotg, linux-oracle vulnerabilities Ubuntu Security Notices (USN) · Oct 27, 2026
- USN-6820-1 linux, linux-gcp, linux-gcp-5.15, linux-lowlatency, linux-lowlatency-hwe-5.15, linux-xilinx-zynqmp vulnerabilities Ubuntu Security Notices (USN) · Oct 27, 2026
- USN-6821-2 linux-gkeop, linux-gkeop-5.15, linux-kvm vulnerabilities Ubuntu Security Notices (USN) · Oct 27, 2026
- USN-6821-3 linux-aws, linux-aws-5.15 vulnerabilities Ubuntu Security Notices (USN) · Oct 27, 2026
- USN-6892-1 linux-ibm-5.15 vulnerabilities Ubuntu Security Notices (USN) · Oct 27, 2026
- USN-6820-2 linux-nvidia vulnerabilities Ubuntu Security Notices (USN) · Oct 27, 2026
- WID-SEC-2024-0773 Linux Kernel: Mehrere Schwachstellen BSI CERT-Bund (WID) · Oct 25, 2026
- DSA-5681-1 linux - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-3840-1 linux - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-3842-1 linux-5.10 - security update Debian Security (DSA / DLA) · Mar 9, 2026
- ICSA-25-226-15 Siemens SINEC OS CISA ICS & IT advisories · Feb 25, 2026
- SSA-613116 SSA-613116: Multiple Vulnerabilities in Third-Party Components in SINEC OS before V3.1 Siemens ProductCERT · Feb 24, 2026
- SUSE-SU-2024:1979-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2024:1983-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2024:2184-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- WID-SEC-2025-0225 Dell PowerProtect Data Domain: Mehrere Schwachstellen BSI CERT-Bund (WID) · Oct 1, 2025
- ALAS2-2024-2549 Moderate: kernel security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Mar 10, 2025
- WID-SEC-2024-0803 Linux Kernel: Schwachstelle ermöglicht Denial of Service BSI CERT-Bund (WID) · Jul 28, 2024
References
- https://git.kernel.org/stable/c/4c3ce64bc9d36ca9164dd6c77ff144c121011aae
- https://git.kernel.org/stable/c/c1d3a84a67db910ce28a871273c992c3d7f9efb5
- https://git.kernel.org/stable/c/dcb4d14268595065c85dc5528056713928e17243
- https://git.kernel.org/stable/c/0da15a70395182ee8cb75716baf00dddc0bea38d
- https://git.kernel.org/stable/c/13cd1daeea848614e585b2c6ecc11ca9c8ab2500
- https://git.kernel.org/stable/c/804bd8650a3a2bf3432375f8c97d5049d845ce56
- https://git.kernel.org/stable/c/83340c66b498e49353530e41542500fc8a4782d6
- https://git.kernel.org/stable/c/359e54a93ab43d32ee1bff3c2f9f10cb9f6b6e79