Description
In the Linux kernel, the following vulnerability has been resolved:
pppoatm: ensure a writable skb header and linear data
In pppoatm_send(), LLC encapsulation checks whether there is sufficient
headroom for the 4-byte LLC header, but does not ensure that the skb header
is writable.
Normal transmit packets passing through ppp_start_xmit() have their header
unshared via skb_cow_head(). However, packets can also reach pppoatm_send()
via PPP channel bridging (PPPIOCBRIDGECHAN) without going through
ppp_start_xmit().
Use skb_cow_head() to ensure both sufficient headroom and a writable
header before pushing the LLC header.
While at it:
- Call pskb_may_pull(skb, 1) before inspecting skb->data[0] to prevent
out-of-bounds reads on zero-length or non-linear frames (e.g. from
bridging).
- Defer SC_COMP_PROT protocol compression until after pppoatm_may_send()
succeeds. This eliminates the temporary skb allocation on admission failure
and completely removes the fragile "undo" heuristic at the nospace label,
avoiding any risk of reading uninitialized headroom or performing an
unbalanced skb_push().
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Linux | Linux | 5.11 | 5.15.222 |
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 | 7.2.8-1 | — |
| Debian 13 | linux | 6.12.113-1 | — |
| Debian 12 | linux | 6.1.190-1 | — |
| Debian 12 | linux-6.12 | 6.12.113-1~deb12u1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Nvidia-BlueField 24.04 LTS | linux-bluefield | 6.8.0-1036.41 | — |
| Ubuntu Nvidia-BlueField 22.04 LTS | linux-bluefield | 5.15.0-1103.105 | — |
| Ubuntu 26.04 LTS | linux | 7.0.0-42.42 | USN-8959-1 |
| Ubuntu 26.04 LTS | linux-aws | 7.0.0-1016.17 | USN-8959-1 |
| Ubuntu 26.04 LTS | linux-azure | 7.0.0-1020.21 | USN-9019-1 |
| Ubuntu 26.04 LTS | linux-azure-fde | 7.0.0-1019.19 | USN-9020-1 |
| Ubuntu 26.04 LTS | linux-gcp | 7.0.0-1016.18 | USN-8959-1 |
| Ubuntu 26.04 LTS | linux-gke | 7.0.0-1010.11 | USN-9020-1 |
| Ubuntu 26.04 LTS | linux-ibm +1 | 7.0.0-1017.17 | USN-8960-1, USN-8959-1 |
| Ubuntu 26.04 LTS | linux-nvidia +1 | No fix yet | — |
| Ubuntu 26.04 LTS | linux-oracle | 7.0.0-1015.16 | USN-8959-1 |
| Ubuntu 26.04 LTS | linux-raspi | 7.0.0-1023.23 | USN-9021-1 |
| Ubuntu 26.04 LTS | linux-realtime | 7.0.0-43.43.1 | USN-9020-1 |
| Ubuntu 26.04 LTS | linux-riscv | 7.0.0-42.42.1 | — |
| Ubuntu 24.04 LTS | linux | 6.8.0-149.149 | USN-9022-1 |
| Ubuntu 24.04 LTS | linux-aws | 6.8.0-1069.74 | USN-9022-1 |
| Ubuntu 24.04 LTS | linux-aws-7.0 | 7.0.0-1017.18~24.04.1 | USN-9020-1 |
| Ubuntu 24.04 LTS | linux-azure | 6.8.0-1073.82 | USN-9022-1 |
| Ubuntu 24.04 LTS | linux-azure-fde | 6.8.0-1071.78 | USN-9039-1 |
| Ubuntu 24.04 LTS | linux-azure-fde-7.0 | 7.0.0-1019.19~24.04.1 | USN-9020-1 |
| Ubuntu 24.04 LTS | linux-gcp | 6.8.0-1073.81 | USN-9022-1 |
| Ubuntu 24.04 LTS | linux-gcp-7.0 | 7.0.0-1017.19~24.04.1 | USN-9020-1 |
| Ubuntu 24.04 LTS | linux-gke | 6.8.0-1068.77 | USN-9022-1 |
| Ubuntu 24.04 LTS | linux-gkeop | 6.8.0-1053.57 | USN-9023-1 |
| Ubuntu 24.04 LTS | linux-hwe-7.0 | 7.0.0-42.42~24.04.1 | USN-8959-1 |
| Ubuntu 24.04 LTS | linux-ibm | 6.8.0-1069.70 | USN-9022-1 |
| Ubuntu 24.04 LTS | linux-lowlatency | 6.8.0-149.149.1 | USN-9022-1 |
| Ubuntu 24.04 LTS | linux-nvidia | 6.8.0-1067.70 | USN-9024-1 |
| Ubuntu 24.04 LTS | linux-nvidia-lowlatency | 6.8.0-1067.70.1 | USN-9040-1 |
| Ubuntu 24.04 LTS | linux-nvidia-tegra | 6.8.0-1039.40 | USN-9091-1 |
| Ubuntu 24.04 LTS | linux-oracle | 6.8.0-1067.71 | USN-9022-1 |
| Ubuntu 24.04 LTS | linux-oracle-7.0 | 7.0.0-1016.18~24.04.1 | USN-9020-1 |
| Ubuntu 24.04 LTS | linux-raspi | 6.8.0-1068.72 | USN-9025-1 |
| Ubuntu 24.04 LTS | linux-riscv +31 | No fix yet | — |
| Ubuntu 24.04 LTS | linux-riscv-7.0 | 7.0.0-42.42.1~24.04.1 | — |
| Ubuntu 24.04 LTS | linux-vmware | 6.8.0-1010.10 | USN-9022-1 |
| Ubuntu 22.04 LTS | linux | 5.15.0-202.212 | USN-8961-1 |
| Ubuntu 22.04 LTS | linux-aws | 5.15.0-1119.126 | USN-8961-1 |
| Ubuntu 22.04 LTS | linux-aws-6.8 | 6.8.0-1069.74~22.04.1 | USN-9024-1 |
| Ubuntu 22.04 LTS | linux-azure | 5.15.0-1125.134 | USN-8961-1 |
| Ubuntu 22.04 LTS | linux-azure-6.8 | 6.8.0-1073.82~22.04.1 | USN-9026-1 |
| Ubuntu 22.04 LTS | linux-azure-fde | 5.15.0-1124.133 | — |
| Ubuntu 22.04 LTS | linux-azure-fde-6.8 | 6.8.0-1071.78~22.04.1 | USN-9026-1 |
| Ubuntu 22.04 LTS | linux-gcp | 5.15.0-1120.130 | USN-8961-1 |
| Ubuntu 22.04 LTS | linux-gcp-6.8 | 6.8.0-1073.81~22.04.1 | USN-9024-1 |
| Ubuntu 22.04 LTS | linux-gke | 5.15.0-1115.121 | USN-8961-1 |
| Ubuntu 22.04 LTS | linux-gkeop | 5.15.0-1102.110 | USN-8961-1 |
| Ubuntu 22.04 LTS | linux-hwe-6.8 | 6.8.0-149.149~22.04.1 | USN-9066-1 |
| Ubuntu 22.04 LTS | linux-ibm | 5.15.0-1113.117 | USN-8961-1 |
| Ubuntu 22.04 LTS | linux-ibm-6.8 | 6.8.0-1069.70~22.04.1 | USN-9024-1 |
| Ubuntu 22.04 LTS | linux-intel-iotg | 5.15.0-1114.120 | USN-8961-1 |
| Ubuntu 22.04 LTS | linux-kvm | 5.15.0-1111.116 | USN-8961-1 |
| Ubuntu 22.04 LTS | linux-lowlatency | 5.15.0-197.207 | USN-8961-1 |
| Ubuntu 22.04 LTS | linux-lowlatency-hwe-6.8 | 6.8.0-149.149.1~22.04.1 | USN-9024-1 |
| Ubuntu 22.04 LTS | linux-nvidia | 5.15.0-1114.115 | USN-8961-1 |
| Ubuntu 22.04 LTS | linux-nvidia-tegra | 5.15.0-1070.72 | USN-8963-1 |
| Ubuntu 22.04 LTS | linux-nvidia-tegra-igx | 5.15.0-1059.59 | USN-8963-1 |
| Ubuntu 22.04 LTS | linux-oracle | 5.15.0-1116.122 | USN-8961-1 |
| Ubuntu 22.04 LTS | linux-oracle-6.8 | 6.8.0-1067.71~22.04.1 | USN-9025-1 |
| Ubuntu 22.04 LTS | linux-raspi | 5.15.0-1113.116 | USN-9029-1 |
| Ubuntu 22.04 LTS | linux-riscv +34 | No fix yet | — |
Show 9 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| 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 | — |
| Ubuntu Pro Realtime 24.04 LTS | linux-raspi-realtime | 6.8.0-2056.58 | USN-9025-1 |
| Ubuntu Pro Realtime 24.04 LTS | linux-realtime | 6.8.1-1064.65 | USN-9023-1 |
| Ubuntu Pro Realtime 24.04 LTS | linux-realtime-6.14 +1 | No fix yet | — |
| Ubuntu Pro Realtime 22.04 LTS | linux-intel-iot-realtime | 5.15.0-1111.115 | USN-8961-1 |
| Ubuntu Pro Realtime 22.04 LTS | linux-realtime | 5.15.0-1118.127 | USN-8961-1 |
| Ubuntu Pro Realtime 22.04 LTS | linux-realtime-6.8 | 6.8.1-1064.65~22.04.1 | USN-9024-1 |
| Ubuntu Pro FIPS-updates 24.04 LTS | linux-aws-fips | 6.8.0-1069.74+fips1 | USN-9023-1 |
| Ubuntu Pro FIPS-updates 24.04 LTS | linux-azure-fips | 6.8.0-1073.82+fips1 | USN-9022-1 |
| Ubuntu Pro FIPS-updates 24.04 LTS | linux-fips | No fix yet | — |
| Ubuntu Pro FIPS-updates 24.04 LTS | linux-gcp-fips | 6.8.0-1073.81+fips1 | USN-9023-1 |
| Ubuntu Pro FIPS-updates 22.04 LTS | linux-aws-fips | 5.15.0-1119.126+fips1 | USN-8961-1 |
| Ubuntu Pro FIPS-updates 22.04 LTS | linux-azure-fips | 5.15.0-1125.134+fips1 | USN-8961-1 |
| Ubuntu Pro FIPS-updates 22.04 LTS | linux-fips | 5.15.0-202.212+fips1 | USN-8961-1 |
| Ubuntu Pro FIPS-updates 22.04 LTS | linux-gcp-fips | 5.15.0-1120.130+fips1 | USN-8961-1 |
| Ubuntu Pro FIPS-preview 22.04 LTS | linux-fips +3 | No fix yet | — |
| Ubuntu Pro 20.04 LTS | linux-aws-5.15 | 5.15.0-1119.126~20.04.1 | USN-8961-1 |
| Ubuntu Pro 20.04 LTS | linux-azure-5.15 | 5.15.0-1125.134~20.04.1 | USN-8961-1 |
| Ubuntu Pro 20.04 LTS | linux-azure-fde-5.15 | 5.15.0-1124.133~20.04.1 | USN-8961-1 |
| Ubuntu Pro 20.04 LTS | linux-gcp-5.15 | 5.15.0-1120.130~20.04.1 | USN-8961-1 |
| Ubuntu Pro 20.04 LTS | linux-hwe-5.15 | 5.15.0-202.212~20.04.1 | USN-8961-1 |
| Ubuntu Pro 20.04 LTS | linux-ibm-5.15 | 5.15.0-1113.117~20.04.1 | USN-8961-1 |
| Ubuntu Pro 20.04 LTS | linux-intel-iotg-5.15 | 5.15.0-1114.120~20.04.1 | USN-8961-1 |
| Ubuntu Pro 20.04 LTS | linux-lowlatency-hwe-5.15 | 5.15.0-197.207~20.04.1 | USN-8961-1 |
| Ubuntu Pro 20.04 LTS | linux-nvidia-tegra-5.15 | 5.15.0-1070.72~20.04.1 | USN-8963-1 |
| Ubuntu Pro 20.04 LTS | linux-oracle-5.15 | 5.15.0-1116.122~20.04.1 | USN-8961-1 |
| Ubuntu Pro 20.04 LTS | linux-riscv-5.15 | 5.15.0-1113.117~20.04.2 | — |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | kernel-source | 7.2.10-1.1 | openSUSE-SU-2026:12131-1 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | kernel | 6.6.158.1-1 | — |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 9 | kernel-uek +34 | 6.12.0-208.112.5.el10uek | ELSA-2026-500572 |
| Oracle Linux 8 | bpftool +18 | 5.15.0-326.222.4.el9uek | ELSA-2026-500574 |
Advisories 21
- USN-9091-1 linux-nvidia-tegra vulnerabilities Ubuntu Security Notices (USN) · Nov 13, 2026
- USN-9066-1 linux-hwe-6.8 vulnerabilities Ubuntu Security Notices (USN) · Nov 12, 2026
- USN-9021-1 linux-raspi vulnerabilities Ubuntu Security Notices (USN) · Nov 12, 2026
- USN-9022-1 linux, linux-aws, linux-azure, linux-azure-fips, linux-gcp, linux-gke, linux-ibm, linux-lowlatency, linux-oracle, linux-vmware vulnerabilities Ubuntu Security Notices (USN) · Nov 12, 2026
- USN-9024-1 linux-aws-6.8, linux-gcp-6.8, linux-ibm-6.8, linux-lowlatency-hwe-6.8, linux-nvidia, linux-realtime-6.8 vulnerabilities Ubuntu Security Notices (USN) · Nov 12, 2026
- USN-9026-1 linux-azure-6.8, linux-azure-fde-6.8 vulnerabilities Ubuntu Security Notices (USN) · Nov 12, 2026
- USN-9039-1 linux-azure-fde vulnerabilities Ubuntu Security Notices (USN) · Nov 12, 2026
- WID-SEC-2026-3743 Linux Kernel: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 12, 2026
- USN-9040-1 linux-nvidia-lowlatency vulnerabilities Ubuntu Security Notices (USN) · Nov 12, 2026
- USN-8961-1 linux, linux-aws, linux-aws-5.15, linux-aws-fips, linux-azure, linux-azure-5.15, linux-azure-fde-5.15, linux-azure-fips, linux-fips, linux-gcp, linux-gcp-5.15, linux-gcp-fips, linux-gke, linux-gkeop, linux-hwe-5.15, linux-ibm, linux-ibm-5.15, linux-intel-iot-realtime, linux-intel-iotg, linux-intel-iotg-5.15, linux-kvm, linux-lowlatency, linux-lowlatency-hwe-5.15, linux-nvidia, linux-oracle, linux-oracle-5.15, linux-realtime vulnerabilities Ubuntu Security Notices (USN) · Nov 12, 2026
- USN-9020-1 linux-aws-7.0, linux-azure-fde, linux-azure-fde-7.0, linux-gcp-7.0, linux-gke, linux-oracle-7.0, linux-realtime vulnerabilities Ubuntu Security Notices (USN) · Nov 12, 2026
- USN-8959-1 linux, linux-aws, linux-gcp, linux-hwe-7.0, linux-ibm, linux-oracle vulnerabilities Ubuntu Security Notices (USN) · Nov 12, 2026
- USN-8963-1 linux-nvidia-tegra, linux-nvidia-tegra-5.15, linux-nvidia-tegra-igx vulnerabilities Ubuntu Security Notices (USN) · Nov 12, 2026
- USN-9025-1 linux-oracle-6.8, linux-raspi, linux-raspi-realtime vulnerabilities Ubuntu Security Notices (USN) · Nov 12, 2026
- USN-9023-1 linux-aws-fips, linux-gcp-fips, linux-gkeop, linux-realtime vulnerabilities Ubuntu Security Notices (USN) · Nov 12, 2026
- USN-9019-1 linux-azure vulnerabilities Ubuntu Security Notices (USN) · Nov 12, 2026
- USN-9029-1 linux-raspi vulnerabilities Ubuntu Security Notices (USN) · Nov 12, 2026
- USN-8960-1 linux-oem-7.0 vulnerabilities Ubuntu Security Notices (USN) · Nov 12, 2026
- ELSA-2026-500572 Important: Unbreakable Enterprise kernel security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Nov 2, 2026
- ELSA-2026-500574 Important: Unbreakable Enterprise kernel security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Nov 2, 2026
- openSUSE-SU-2026:12131-1 kernel-devel-7.2.10-1.1 on GA media SUSE / openSUSE Security Updates · Oct 15, 2026
References
- https://git.kernel.org/stable/c/208ccc4d08b1897451e9ba01c016bf93ff107966
- https://git.kernel.org/stable/c/e6cd1bba7d113c15c00ac63671213a096fe4d686
- https://git.kernel.org/stable/c/ffc448eb54f5ba80d4212c1e870cdb92b0f709fa
- https://git.kernel.org/stable/c/8e66c5969acd859ba72fb0a7fa895623fc1b3769
- https://git.kernel.org/stable/c/e2f5529b0016db7d34f411408607f5cf395a542e
- https://git.kernel.org/stable/c/30992fe39e65589ed8e000425e088fa74994b811
- https://git.kernel.org/stable/c/ecc7253683a3c55caa868ce0ee530fcb0044bd3c