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Critical · 9.8 CVE-2026-68136 EUVD-2026-55517GHSA-p4gp-483j-wr28

net: gro: fix double aggregation of flush-marked skbs

Published Aug 10, 2026 · Updated Oct 19, 2026 · Assigned by Linux

Vendor: Linux Product: Linux Package: kernel Package: linux Package: linux Package: linux-6.12 Package: linux-allwinner-5.19 Package: linux-aws Package: linux-aws-5.0 Package: linux-aws-5.11 Package: linux-aws-5.13 Package: linux-aws-5.15 Package: linux-aws-5.19 Package: linux-aws-5.3 Package: linux-aws-5.8 Package: linux-aws-6.14 Package: linux-aws-6.17 Package: linux-aws-6.2 Package: linux-aws-6.5 Package: linux-aws-6.8 Package: linux-aws-7.0 Package: linux-aws-fips Package: linux-azure Package: linux-azure-5.11 Package: linux-azure-5.13 Package: linux-azure-5.15 Package: linux-azure-5.19 Package: linux-azure-5.3 Package: linux-azure-5.8 Package: linux-azure-6.11 Package: linux-azure-6.14 Package: linux-azure-6.17 Package: linux-azure-6.2 Package: linux-azure-6.5 Package: linux-azure-6.8 Package: linux-azure-7.0 Package: linux-azure-edge Package: linux-azure-fde Package: linux-azure-fde-5.15 Package: linux-azure-fde-5.19 Package: linux-azure-fde-6.14 Package: linux-azure-fde-6.17 Package: linux-azure-fde-6.2 Package: linux-azure-fde-6.8 Package: linux-azure-fde-7.0 Package: linux-azure-fips Package: linux-azure-nvidia Package: linux-azure-nvidia-6.14 Package: linux-bluefield Package: linux-fips Package: linux-gcp Package: linux-gcp-5.11 Package: linux-gcp-5.13 Package: linux-gcp-5.15 Package: linux-gcp-5.19 Package: linux-gcp-5.3 Package: linux-gcp-5.8 Package: linux-gcp-6.11 Package: linux-gcp-6.14 Package: linux-gcp-6.17 Package: linux-gcp-6.2 Package: linux-gcp-6.5 Package: linux-gcp-6.8 Package: linux-gcp-7.0 Package: linux-gcp-fips Package: linux-gke Package: linux-gke-4.15 Package: linux-gke-5.15 Package: linux-gke-5.4 Package: linux-gkeop Package: linux-gkeop-5.15 Package: linux-gkeop-5.4 Package: linux-hwe Package: linux-hwe-5.11 Package: linux-hwe-5.13 Package: linux-hwe-5.15 Package: linux-hwe-5.19 Package: linux-hwe-5.8 Package: linux-hwe-6.11 Package: linux-hwe-6.14 Package: linux-hwe-6.17 Package: linux-hwe-6.2 Package: linux-hwe-6.5 Package: linux-hwe-6.8 Package: linux-hwe-7.0 Package: linux-hwe-edge Package: linux-ibm Package: linux-ibm-5.15 Package: linux-ibm-6.8 Package: linux-intel-5.13 Package: linux-intel-iot-realtime Package: linux-intel-iotg Package: linux-intel-iotg-5.15 Package: linux-kvm Package: linux-lowlatency Package: linux-lowlatency-hwe-5.15 Package: linux-lowlatency-hwe-5.19 Package: linux-lowlatency-hwe-6.11 Package: linux-lowlatency-hwe-6.2 Package: linux-lowlatency-hwe-6.5 Package: linux-lowlatency-hwe-6.8 Package: linux-nvidia Package: linux-nvidia-6.11 Package: linux-nvidia-6.17 Package: linux-nvidia-6.2 Package: linux-nvidia-6.5 Package: linux-nvidia-6.8 Package: linux-nvidia-7.0 Package: linux-nvidia-bos Package: linux-nvidia-lowlatency Package: linux-nvidia-tegra Package: linux-nvidia-tegra-5.15 Package: linux-nvidia-tegra-igx Package: linux-oem Package: linux-oem-5.10 Package: linux-oem-5.13 Package: linux-oem-5.14 Package: linux-oem-5.17 Package: linux-oem-5.6 Package: linux-oem-6.0 Package: linux-oem-6.1 Package: linux-oem-6.11 Package: linux-oem-6.14 Package: linux-oem-6.17 Package: linux-oem-6.5 Package: linux-oem-6.8 Package: linux-oem-7.0 Package: linux-oracle Package: linux-oracle-5.0 Package: linux-oracle-5.11 Package: linux-oracle-5.13 Package: linux-oracle-5.15 Package: linux-oracle-5.3 Package: linux-oracle-5.8 Package: linux-oracle-6.14 Package: linux-oracle-6.17 Package: linux-oracle-6.5 Package: linux-oracle-6.8 Package: linux-oracle-7.0 Package: linux-raspi Package: linux-raspi-realtime Package: linux-raspi2 Package: linux-realtime Package: linux-realtime-6.14 Package: linux-realtime-6.17 Package: linux-realtime-6.8 Package: linux-riscv Package: linux-riscv-5.11 Package: linux-riscv-5.15 Package: linux-riscv-5.19 Package: linux-riscv-5.8 Package: linux-riscv-6.14 Package: linux-riscv-6.17 Package: linux-riscv-6.5 Package: linux-riscv-6.8 Package: linux-riscv-7.0 Package: linux-starfive-5.19 Package: linux-starfive-6.2 Package: linux-starfive-6.5 Package: linux-vmware Package: linux-xilinx Package: linux-xilinx-zynqmp Platform: Linux Ecosystem: Azure Linux Ecosystem: Debian Ecosystem: Ubuntu

Description

In the Linux kernel, the following vulnerability has been resolved:

net: gro: fix double aggregation of flush-marked skbs

Commit 0ab03f353d36 ("net-gro: Fix GRO flush when receiving a GSO
packet.") added a flush check to skb_gro_receive(), but
skb_gro_receive_list() lacks the same validation.

As a result, packets marked with NAPI_GRO_CB(skb)->flush may still be
re-aggregated.

This allows already-GRO'd packets with existing frag_list to be
re-aggregated into a new GRO session, corrupting the frag_list chain
structure. When skb_segment() attempts to unpack these malformed packets,
it encounters invalid state and triggers a kernel panic.

Scenario (Tethering/Device forwarding):
1. Driver: Generated aggregated packet P1 via LRO with frag_list
2. Dev A: Receives aggregated fraglist packet and flush flag set
3. Dev A: Re-enters GRO, skb_gro_receive_list() is called
4. Missing flush check allows re-aggregation despite flush flag
5. Frag_list chain becomes corrupted (loops or dangling refs)
6. Dev B: TX path calls skb_segment(), crashes on corrupted frag_list

Root cause in skb_segment():
The check at line ~4891:
if (hsize <= 0 && i >= nfrags && skb_headlen(list_skb) &&
(skb_headlen(list_skb) == len || sg)) {

When frag_list is corrupted by double aggregation, when list_skb is
a NULL pointer from skb->next, skb_headlen(list_skb) dereference
NULL/corrupted pointers occurs.

Call Trace:
skb_headlen(NULL skb)
skb_segment
tcp_gso_segment
tcp4_gso_segment
inet_gso_segment
skb_mac_gso_segment
__skb_gso_segment
skb_gso_segment
validate_xmit_skb
validate_xmit_skb_list
sch_direct_xmit
qdisc_restart
__qdisc_run
qdisc_run
net_tx_action

Fix: Add NAPI_GRO_CB(skb)->flush validation to the early-return check in
skb_gro_receive_list(), matching the defensive programming pattern of
skb_gro_receive().

Affected products

VendorProductAffectedFixed
Linux Linux 5.6 5.10.266

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.

ReleasePackageFixed inAdvisory
Debian 14 linux 7.1.6-1 —
Debian 13 linux 6.12.101-1 —
Debian 12 linux 6.1.187-1 —
Debian 12 linux-6.12 6.12.101-1~deb12u1 —
ReleasePackageFixed inAdvisory
Ubuntu Nvidia-BlueField 24.04 LTS linux-bluefield 6.8.0-1033.38 —
Ubuntu Nvidia-BlueField 22.04 LTS linux-bluefield No fix yet —
Ubuntu 26.04 LTS linux 7.0.0-38.38 USN-8887-1
Ubuntu 26.04 LTS linux-aws +1 7.0.0-1014.14 USN-8887-1
Ubuntu 26.04 LTS linux-azure 7.0.0-1017.17 USN-8888-1
Ubuntu 26.04 LTS linux-azure-fde 7.0.0-1016.16 USN-8888-1
Ubuntu 26.04 LTS linux-gke 7.0.0-1008.9 USN-8887-1
Ubuntu 26.04 LTS linux-ibm +1 7.0.0-1015.15 USN-8889-1, USN-8887-1
Ubuntu 26.04 LTS linux-nvidia 7.0.0-1025.26 USN-9043-1
Ubuntu 26.04 LTS linux-nvidia-bos 7.0.0-2022.23 USN-9003-1
Ubuntu 26.04 LTS linux-oracle 7.0.0-1013.13 USN-8887-1
Ubuntu 26.04 LTS linux-raspi 7.0.0-1023.23 USN-9021-1
Ubuntu 26.04 LTS linux-riscv +1 7.0.0-38.38.1 USN-8887-1
Ubuntu 24.04 LTS linux 6.8.0-147.147 USN-8917-1
Ubuntu 24.04 LTS linux-aws +1 6.8.0-1067.70 USN-9024-1, USN-8917-1
Ubuntu 24.04 LTS linux-aws-7.0 +1 7.0.0-1014.14~24.04.1 USN-8887-3, USN-8887-2
Ubuntu 24.04 LTS linux-azure-7.0 7.0.0-1017.17~24.04.1 USN-8888-2
Ubuntu 24.04 LTS linux-azure-fde 6.8.0-1069.76 USN-8918-1
Ubuntu 24.04 LTS linux-azure-fde-7.0 7.0.0-1016.16~24.04.1 USN-8888-2
Ubuntu 24.04 LTS linux-gcp +1 6.8.0-1071.79 USN-8918-1, USN-8917-1
Ubuntu 24.04 LTS linux-gke 6.8.0-1066.74 USN-8917-1
Ubuntu 24.04 LTS linux-gkeop 6.8.0-1052.56 USN-8917-1
Ubuntu 24.04 LTS linux-hwe-7.0 7.0.0-38.38~24.04.4 USN-8887-3
Ubuntu 24.04 LTS linux-ibm 6.8.0-1067.68 USN-8917-1
Ubuntu 24.04 LTS linux-lowlatency 6.8.0-147.147.1 USN-8917-1
Ubuntu 24.04 LTS linux-nvidia-7.0 7.0.0-1024.25~24.04.1 USN-9003-1
Ubuntu 24.04 LTS linux-nvidia-lowlatency 6.8.0-1067.70.1 USN-9040-1
Ubuntu 24.04 LTS linux-nvidia-tegra 6.8.0-1035.38 USN-8781-1
Ubuntu 24.04 LTS linux-oracle 6.8.0-1064.67 USN-8917-1
Ubuntu 24.04 LTS linux-oracle-7.0 7.0.0-1013.13~24.04.1 USN-8887-3
Ubuntu 24.04 LTS linux-raspi 6.8.0-1068.72 USN-9025-1
Ubuntu 24.04 LTS linux-riscv +29 No fix yet —
Ubuntu 24.04 LTS linux-riscv-7.0 7.0.0-38.38.1~24.04.1 —
Ubuntu 24.04 LTS linux-vmware 6.8.0-1008.8 —
Ubuntu 22.04 LTS linux +50 No fix yet —
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-6.8 6.8.0-1073.82~22.04.1 USN-9026-1
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-6.8 6.8.0-1073.81~22.04.1 USN-9024-1
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-6.8 6.8.0-1069.70~22.04.1 USN-9024-1
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-oracle-6.8 6.8.0-1067.71~22.04.1 USN-9025-1
Show 9 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
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 6.8.1-1062.63 USN-8917-1
Ubuntu Pro Realtime 24.04 LTS linux-realtime-6.14 +1 No fix yet —
Ubuntu Pro Realtime 22.04 LTS linux-realtime +1 No fix yet —
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 6.8.0-1067.70+fips1 USN-8917-1
Ubuntu Pro FIPS-updates 24.04 LTS linux-fips 6.8.0-147.147+fips1 USN-8917-1
Ubuntu Pro FIPS-updates 24.04 LTS linux-gcp-fips +1 6.8.0-1071.79+fips1 USN-8918-1, USN-8917-1
Ubuntu Pro FIPS-updates 22.04 LTS linux-fips +3 No fix yet —
Ubuntu Pro FIPS-preview 22.04 LTS linux-fips +3 No fix yet —
Ubuntu Pro 20.04 LTS linux-aws-5.15 +10 No fix yet —

AlmaLinux

Errata ↗
ReleasePackageFixed inAdvisory
AlmaLinux 10 rv +74 6.12.0-211.69.1.el10_2 ALSA-2026:91565
AlmaLinux 8 kernel-rt +9 4.18.0-553.178.1.rt7.519.el8_10 ALSA-2026:89082
AlmaLinux 8 perf +24 4.18.0-553.178.1.el8_10 ALSA-2026:89083

Rocky Linux

Errata ↗
ReleasePackageFixed inAdvisory
Rocky Linux 10 kernel 6.12.0-211.69.1.el10_2 RLSA-2026:91565
Rocky Linux 8 kernel 4.18.0-553.178.1.el8_10 RLSA-2026:89083
Rocky Linux 8 kernel-rt 4.18.0-553.178.1.rt7.519.el8_10 RLSA-2026:89082
ReleasePackageFixed inAdvisory
SLES 15 SP7 kernel-64kb +7 6.4.0-150700.53.81.1 SUSE-SU-2026:4254-1
SLES 15 SP7 kernel-default-base 6.4.0-150700.53.81.1.150700.17.45.1 SUSE-SU-2026:4254-1
SLES 15 SP6 kernel-64kb +6 6.4.0-150600.23.135.1 SUSE-SU-2026:4369-1
SLES 15 SP6 kernel-default-base 6.4.0-150600.23.135.1.150600.12.62.4 SUSE-SU-2026:4369-1
SLES 15 SP5 kernel-64kb +6 5.14.21-150500.55.189.1 SUSE-SU-2026:4595-1
SLES 15 SP5 kernel-default-base 5.14.21-150500.55.189.1.150500.6.87.4 SUSE-SU-2026:4595-1
SLES 15 SP4 kernel-64kb +2 5.14.21-150400.24.240.2 SUSE-SU-2026:4284-1
SLES 15 SP4 kernel-default-base 5.14.21-150400.24.240.2.150400.24.120.2 SUSE-SU-2026:4284-1
SLES 15 SP4 kernel-docs +3 5.14.21-150400.24.240.1 SUSE-SU-2026:4284-1
Show 18 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
SLES for SAP 16.0 kernel-64kb +8 6.12.0-160000.38.1 SUSE-SU-2026:23902-1
SLES for SAP 16.0 kernel-default-base 6.12.0-160000.38.1.160000.2.23 SUSE-SU-2026:23902-1
SLES for SAP 15 SP6 kernel-default-base 6.4.0-150600.23.135.1.150600.12.62.4 SUSE-SU-2026:4369-1
SLES for SAP 15 SP6 kernel-docs +4 6.4.0-150600.23.135.1 SUSE-SU-2026:4369-1
SLES for SAP 15 SP5 kernel-default-base 5.14.21-150500.55.189.1.150500.6.87.4 SUSE-SU-2026:4595-1
SLES for SAP 15 SP5 kernel-docs +4 5.14.21-150500.55.189.1 SUSE-SU-2026:4595-1
SLES for SAP 15 SP4 kernel-default 5.14.21-150400.24.240.2 SUSE-SU-2026:4284-1
SLES for SAP 15 SP4 kernel-default-base 5.14.21-150400.24.240.2.150400.24.120.2 SUSE-SU-2026:4284-1
SLES for SAP 15 SP4 kernel-docs +3 5.14.21-150400.24.240.1 SUSE-SU-2026:4284-1
SLES 16.0 kernel-64kb +8 6.12.0-160000.38.1 SUSE-SU-2026:23902-1, SUSE-SU-2026:23897-1
SLES 16.0 kernel-default-base 6.12.0-160000.38.1.160000.2.23 SUSE-SU-2026:23902-1
SLE Micro 6.2 kernel-default-base 6.12.0-160000.38.1.160000.2.23 SUSE-SU-2026:23887-1
SLE Micro 6.2 kernel-rt +5 6.12.0-160000.38.1 SUSE-SU-2026:23887-1, SUSE-SU-2026:23881-1
SLE Micro 6.1 kernel-default-base 6.4.0-52.1.21.34 SUSE-SU-2026:23529-1
SLE Micro 6.1 kernel-rt +4 6.4.0-52.1 SUSE-SU-2026:23529-1, SUSE-SU-2026:23528-1
SLE Micro 6.0 kernel-default-base 6.4.0-52.1.21.36 SUSE-SU-2026:23481-1
SLE Micro 6.0 kernel-rt +4 6.4.0-52.1 SUSE-SU-2026:23481-1, SUSE-SU-2026:23477-1
SLE Micro 5.5 kernel-default-base 5.14.21-150500.55.189.1.150500.6.87.4 SUSE-SU-2026:4595-1
SLE Micro 5.5 kernel-rt +1 5.14.21-150500.13.161.1 SUSE-SU-2026:4347-1
SLE Micro 5.5 kernel-source +1 5.14.21-150500.55.189.1 SUSE-SU-2026:4595-1
SLE Micro 5.4 kernel-default 5.14.21-150400.24.240.2 SUSE-SU-2026:4284-1
SLE Micro 5.4 kernel-default-base 5.14.21-150400.24.240.2.150400.24.120.2 SUSE-SU-2026:4284-1
SLE Micro 5.4 kernel-rt +1 5.14.21-150400.15.186.1 SUSE-SU-2026:4279-1
SLE Micro 5.4 kernel-source 5.14.21-150400.24.240.1 SUSE-SU-2026:4284-1
SLE Micro 5.3 kernel-default 5.14.21-150400.24.240.2 SUSE-SU-2026:4284-1
SLE Micro 5.3 kernel-default-base 5.14.21-150400.24.240.2.150400.24.120.2 SUSE-SU-2026:4284-1
SLE Micro 5.3 kernel-rt +1 5.14.21-150400.15.186.1 SUSE-SU-2026:4279-1
SLE Micro 5.3 kernel-source 5.14.21-150400.24.240.1 SUSE-SU-2026:4284-1
SLE Live Patching 15 SP7 kernel-default 6.4.0-150700.53.81.1 SUSE-SU-2026:4254-1
SLE Live Patching 15 SP7 kernel-livepatch-SLE15-SP7-RT_Update_20 1-150700.1.3.1 SUSE-SU-2026:4120-1
SLE Live Patching 15 SP7 kernel-livepatch-SLE15-SP7_Update_21 1-150700.15.3.1 SUSE-SU-2026:4254-1
SLE Live Patching 15 SP6 kernel-default 6.4.0-150600.23.135.1 SUSE-SU-2026:4369-1
SLE Live Patching 15 SP6 kernel-livepatch-SLE15-SP6_Update_31 1-150600.13.3.4 SUSE-SU-2026:4369-1
SLE Live Patching 15 SP5 kernel-default 5.14.21-150500.55.189.1 SUSE-SU-2026:4595-1
SLE Live Patching 15 SP5 kernel-livepatch-SLE15-SP5_Update_45 1-150500.11.5.3 SUSE-SU-2026:4595-1
SLE Live Patching 15 SP4 kernel-default 5.14.21-150400.24.240.2 SUSE-SU-2026:4284-1
SLE Live Patching 15 SP4 kernel-livepatch-SLE15-SP4_Update_59 1-150400.9.5.1 SUSE-SU-2026:4284-1
SLE HPC 15 SP5 kernel-64kb +5 5.14.21-150500.55.189.1 SUSE-SU-2026:4595-1
SLE HPC 15 SP5 kernel-default-base 5.14.21-150500.55.189.1.150500.6.87.4 SUSE-SU-2026:4595-1
SLE HPC 15 SP4 kernel-64kb +1 5.14.21-150400.24.240.2 SUSE-SU-2026:4284-1
SLE HPC 15 SP4 kernel-default-base 5.14.21-150400.24.240.2.150400.24.120.2 SUSE-SU-2026:4284-1
SLE HPC 15 SP4 kernel-docs +3 5.14.21-150400.24.240.1 SUSE-SU-2026:4284-1
SUSE Real Time Module 15 SP7 kernel-rt +2 6.4.0-150700.7.75.1 SUSE-SU-2026:4120-1
ReleasePackageFixed inAdvisory
openSUSE Leap 16.0 kernel-default-base 6.12.0-160000.38.1.160000.2.22 openSUSE-SU-2026:21910-1
openSUSE Leap 16.0 kernel-rt +11 6.12.0-160000.38.1 openSUSE-SU-2026:21910-1

Amazon Linux

ReleasePackageFixed inAdvisory
Amazon Linux 2023 kernel-livepatch-6.18.44-99.149 +2 1:1.0-0.amzn2023 ALAS2023-2026-2143, ALAS2023-2026-2110, ALAS2023-2026-2106
Amazon Linux 2023 perf +11 1:6.1.186-228.374.amzn2023 ALAS2023-2026-2143
Amazon Linux 2023 perf6.12 +11 1:6.12.103-127.188.amzn2023 ALAS2023-2026-2110
Amazon Linux 2023 perf6.18 +12 1:6.18.44-99.149.amzn2023 ALAS2023-2026-2106

Azure Linux

ReleasePackageFixed inAdvisory
Azure Linux 3 kernel 6.6.157.1-1 —

Oracle Linux

ReleasePackageFixed inAdvisory
Oracle Linux 10 rv +29 6.12.0-211.69.1.el10_2 ELSA-2026-91565
Oracle Linux 9 kernel-uek +34 6.12.0-206.104.3.3.el10uek ELSA-2026-500374, ELSA-2026-500248
Oracle Linux 8 perf +19 4.18.0-553.178.1.el8_10 ELSA-2026-89083

Advisories 47

References