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High · 7.5 CVE-2026-23095 EUVD-2026-5447GHSA-fg3v-8p2h-99jg

gue: Fix skb memleak with inner IP protocol 0.

Published Feb 4, 2026 · Updated Nov 10, 2026 · Assigned by Linux

Vendor: Linux Product: Linux Package: kernel Package: linux Package: linux 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-5.4 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-fips Package: linux-aws-hwe Package: linux-azure Package: linux-azure-4.15 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-5.4 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-edge Package: linux-azure-fde Package: linux-azure-fde-5.19 Package: linux-azure-fde-6.14 Package: linux-azure-fde-6.2 Package: linux-azure-fde-6.8 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-4.15 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-5.4 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-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-5.4 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-edge Package: linux-ibm Package: linux-ibm-5.15 Package: linux-ibm-5.4 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-iot 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-lts-xenial 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-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-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-5.4 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-raspi Package: linux-raspi-5.4 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-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:

gue: Fix skb memleak with inner IP protocol 0.

syzbot reported skb memleak below. [0]

The repro generated a GUE packet with its inner protocol 0.

gue_udp_recv() returns -guehdr->proto_ctype for "resubmit"
in ip_protocol_deliver_rcu(), but this only works with
non-zero protocol number.

Let's drop such packets.

Note that 0 is a valid number (IPv6 Hop-by-Hop Option).

I think it is not practical to encap HOPOPT in GUE, so once
someone starts to complain, we could pass down a resubmit
flag pointer to distinguish two zeros from the upper layer:

* no error
* resubmit HOPOPT

[0]
BUG: memory leak
unreferenced object 0xffff888109695a00 (size 240):
comm "syz.0.17", pid 6088, jiffies 4294943096
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00 40 c2 10 81 88 ff ff 00 00 00 00 00 00 00 00 .@..............
backtrace (crc a84b336f):
kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
slab_post_alloc_hook mm/slub.c:4958 [inline]
slab_alloc_node mm/slub.c:5263 [inline]
kmem_cache_alloc_noprof+0x3b4/0x590 mm/slub.c:5270
__build_skb+0x23/0x60 net/core/skbuff.c:474
build_skb+0x20/0x190 net/core/skbuff.c:490
__tun_build_skb drivers/net/tun.c:1541 [inline]
tun_build_skb+0x4a1/0xa40 drivers/net/tun.c:1636
tun_get_user+0xc12/0x2030 drivers/net/tun.c:1770
tun_chr_write_iter+0x71/0x120 drivers/net/tun.c:1999
new_sync_write fs/read_write.c:593 [inline]
vfs_write+0x45d/0x710 fs/read_write.c:686
ksys_write+0xa7/0x170 fs/read_write.c:738
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xa4/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Affected products

VendorProductAffectedFixed
Linux Linux 3.18 5.10.249

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 6.18.8-1 —
Debian 13 linux 6.12.69-1 DSA-6126-1
Debian 12 linux 6.1.162-1 DSA-6127-1
Debian 11 linux 5.10.249-1 DLA-4475-1
Debian 11 linux-6.1 6.1.162-1~deb11u1 DLA-4476-1
ReleasePackageFixed inAdvisory
Ubuntu Nvidia-BlueField 24.04 LTS linux-bluefield 6.8.0-1022.26 —
Ubuntu Nvidia-BlueField 22.04 LTS linux-bluefield 5.15.0-1089.91 —
Ubuntu 25.10 linux +8 No fix yet —
Ubuntu 24.04 LTS linux 6.8.0-117.117 USN-8278-1
Ubuntu 24.04 LTS linux-aws 6.8.0-1055.58 USN-8278-1
Ubuntu 24.04 LTS linux-azure 6.8.0-1056.62 USN-8278-2
Ubuntu 24.04 LTS linux-azure-6.17 6.17.0-1021.21~24.04.1 USN-8604-1
Ubuntu 24.04 LTS linux-azure-fde 6.8.0-1058.65 —
Ubuntu 24.04 LTS linux-azure-fde-6.17 6.17.0-1018.18~24.04.1 USN-8605-1
Ubuntu 24.04 LTS linux-azure-nvidia 6.8.0-1039.42 —
Ubuntu 24.04 LTS linux-gcp 6.8.0-1058.61 USN-8278-1
Ubuntu 24.04 LTS linux-gcp-6.17 6.17.0-1021.24~24.04.1 USN-8570-1
Ubuntu 24.04 LTS linux-gke 6.8.0-1054.60 USN-8278-1
Ubuntu 24.04 LTS linux-gkeop 6.8.0-1041.44 USN-8278-1
Ubuntu 24.04 LTS linux-hwe-6.17 6.17.0-41.41~24.04.1 —
Ubuntu 24.04 LTS linux-ibm 6.8.0-1055.56 USN-8278-1
Ubuntu 24.04 LTS linux-lowlatency 6.8.0-117.117.1 USN-8278-1
Ubuntu 24.04 LTS linux-nvidia 6.8.0-1054.57 USN-8289-1
Ubuntu 24.04 LTS linux-nvidia-6.17 6.17.0-1031.31 USN-8669-1
Ubuntu 24.04 LTS linux-nvidia-lowlatency 6.8.0-1054.57.1 USN-8289-1
Ubuntu 24.04 LTS linux-nvidia-tegra 6.8.0-1024.24 USN-8296-2
Ubuntu 24.04 LTS linux-oem-6.17 6.17.0-1030.30 USN-8594-1
Ubuntu 24.04 LTS linux-oracle 6.8.0-1054.55 —
Ubuntu 24.04 LTS linux-oracle-6.17 6.17.0-1019.19~24.04.3 USN-8570-2
Ubuntu 24.04 LTS linux-raspi 6.8.0-1056.60 USN-8278-1
Ubuntu 24.04 LTS linux-riscv +20 No fix yet —
Ubuntu 24.04 LTS linux-xilinx 6.8.0-1032.33 USN-8499-1
Ubuntu 22.04 LTS linux 5.15.0-176.186 USN-8180-1
Ubuntu 22.04 LTS linux-aws 5.15.0-1105.112 USN-8180-1
Ubuntu 22.04 LTS linux-aws-6.8 6.8.0-1057.60~22.04.1 —
Ubuntu 22.04 LTS linux-azure 5.15.0-1110.119 USN-8180-3
Ubuntu 22.04 LTS linux-azure-6.8 6.8.0-1059.65~22.04.1 USN-8440-1
Ubuntu 22.04 LTS linux-azure-fde 5.15.0-1114.123 —
Ubuntu 22.04 LTS linux-azure-fde-6.8 6.8.0-1058.65~22.04.1 —
Ubuntu 22.04 LTS linux-gcp 5.15.0-1105.114 USN-8180-1
Ubuntu 22.04 LTS linux-gcp-6.8 6.8.0-1060.63~22.04.1 —
Ubuntu 22.04 LTS linux-gke 5.15.0-1101.107 USN-8180-1
Ubuntu 22.04 LTS linux-gkeop 5.15.0-1088.96 USN-8180-1
Ubuntu 22.04 LTS linux-hwe-6.8 6.8.0-124.124~22.04.1 —
Ubuntu 22.04 LTS linux-ibm +1 5.15.0-1099.102 USN-8180-6, USN-8180-5
Ubuntu 22.04 LTS linux-ibm-6.8 6.8.0-1055.56~22.04.1 USN-8278-1
Ubuntu 22.04 LTS linux-intel-iotg 5.15.0-1100.106 USN-8180-3
Ubuntu 22.04 LTS linux-kvm 5.15.0-1097.102 USN-8180-3
Ubuntu 22.04 LTS linux-lowlatency 5.15.0-175.185 USN-8180-1
Ubuntu 22.04 LTS linux-lowlatency-hwe-6.8 6.8.0-117.117.1~22.04.1 USN-8278-1
Ubuntu 22.04 LTS linux-nvidia 5.15.0-1100.101 USN-8180-1
Ubuntu 22.04 LTS linux-nvidia-6.8 6.8.0-1054.57~22.04.1 USN-8289-2
Ubuntu 22.04 LTS linux-nvidia-tegra 5.15.0-1057.57 USN-8187-1
Ubuntu 22.04 LTS linux-nvidia-tegra-igx 5.15.0-1046.46 USN-8187-1
Ubuntu 22.04 LTS linux-oracle 5.15.0-1102.108 USN-8180-1
Ubuntu 22.04 LTS linux-oracle-6.8 6.8.0-1054.55~22.04.1 —
Ubuntu 22.04 LTS linux-riscv +32 No fix yet —
Ubuntu 22.04 LTS linux-riscv-6.8 6.8.0-117.117~22.04.1 —
Ubuntu 22.04 LTS linux-xilinx-zynqmp 5.15.0-1070.74 USN-8275-1
Show 18 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 6.8.0-2045.46 USN-8278-1
Ubuntu Pro Realtime 24.04 LTS linux-realtime 6.8.1-1051.52 USN-8278-1
Ubuntu Pro Realtime 24.04 LTS linux-realtime-6.14 No fix yet —
Ubuntu Pro Realtime 24.04 LTS linux-realtime-6.17 6.17.0-1018.20~24.04.1 USN-8570-1
Ubuntu Pro Realtime 22.04 LTS linux-intel-iot-realtime 5.15.0-1097.99 USN-8186-1
Ubuntu Pro Realtime 22.04 LTS linux-realtime 5.15.0-1104.113 USN-8186-1
Ubuntu Pro Realtime 22.04 LTS linux-realtime-6.8 6.8.1-1051.52~22.04.1 USN-8278-1
Ubuntu Pro FIPS 20.04 LTS linux-fips +3 No fix yet —
Ubuntu Pro FIPS 18.04 LTS linux-fips +3 No fix yet —
Ubuntu Pro FIPS 16.04 LTS linux-fips No fix yet —
Ubuntu Pro FIPS-updates 24.04 LTS linux-aws-fips 6.8.0-1055.58+fips1 USN-8278-1
Ubuntu Pro FIPS-updates 24.04 LTS linux-azure-fips 6.8.0-1059.65+fips1 USN-8393-1
Ubuntu Pro FIPS-updates 24.04 LTS linux-fips 6.8.0-116.116+fips1 USN-8296-1
Ubuntu Pro FIPS-updates 24.04 LTS linux-gcp-fips 6.8.0-1058.61+fips1 USN-8278-1
Ubuntu Pro FIPS-updates 22.04 LTS linux-aws-fips 5.15.0-1105.112+fips1 —
Ubuntu Pro FIPS-updates 22.04 LTS linux-azure-fips 5.15.0-1110.119+fips1 USN-8180-4
Ubuntu Pro FIPS-updates 22.04 LTS linux-fips 5.15.0-176.186+fips1 USN-8180-2
Ubuntu Pro FIPS-updates 22.04 LTS linux-gcp-fips 5.15.0-1105.114+fips1 USN-8180-2
Ubuntu Pro FIPS-updates 20.04 LTS linux-fips +3 No fix yet —
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 FIPS-preview 22.04 LTS linux-fips +3 No fix yet —
Ubuntu Pro 20.04 LTS linux +10 No fix yet —
Ubuntu Pro 20.04 LTS linux-aws-5.15 5.15.0-1105.112~20.04.1 USN-8180-1
Ubuntu Pro 20.04 LTS linux-azure-5.15 5.15.0-1110.119~20.04.1 USN-8243-1
Ubuntu Pro 20.04 LTS linux-gcp-5.15 5.15.0-1106.115~20.04.1 USN-8297-1
Ubuntu Pro 20.04 LTS linux-hwe-5.15 5.15.0-176.186~20.04.1 USN-8188-1
Ubuntu Pro 20.04 LTS linux-ibm-5.15 5.15.0-1099.102~20.04.1 USN-8180-5
Ubuntu Pro 20.04 LTS linux-intel-iotg-5.15 5.15.0-1100.106~20.04.1 USN-8180-3
Ubuntu Pro 20.04 LTS linux-lowlatency-hwe-5.15 5.15.0-175.185~20.04.1 USN-8180-1
Ubuntu Pro 20.04 LTS linux-nvidia-tegra-5.15 5.15.0-1057.57~20.04.1 USN-8162-1
Ubuntu Pro 20.04 LTS linux-oracle-5.15 5.15.0-1102.108~20.04.1 USN-8180-3
Ubuntu Pro 20.04 LTS linux-riscv-5.15 5.15.0-1099.103~20.04.1 —
Ubuntu Pro 18.04 LTS linux +12 No fix yet —
Ubuntu Pro 16.04 LTS linux +7 No fix yet —
Ubuntu Pro 14.04 LTS linux-aws +2 No fix yet —
ReleasePackageFixed inAdvisory
SLES 15 SP7 kernel-64kb +7 6.4.0-150700.53.34.1 SUSE-SU-2026:1081-1
SLES 15 SP7 kernel-default-base 6.4.0-150700.53.34.1.150700.17.23.1 SUSE-SU-2026:1081-1
SLES 12 SP5 kernel-syms +2 4.12.14-122.296.1 SUSE-SU-2026:1078-1
Show 8 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
SLES for SAP 16.0 kernel-64kb +8 6.12.0-160000.27.1 SUSE-SU-2026:20931-1
SLES for SAP 16.0 kernel-default-base 6.12.0-160000.27.1.160000.2.8 SUSE-SU-2026:20931-1
SLES 16.0 kernel-64kb +8 6.12.0-160000.27.1 SUSE-SU-2026:20931-1
SLES 16.0 kernel-default-base 6.12.0-160000.27.1.160000.2.8 SUSE-SU-2026:20931-1
SLE Micro 6.2 kernel-default-base 6.12.0-160000.27.1.160000.2.8 SUSE-SU-2026:20838-1
SLE Micro 6.2 kernel-rt +5 6.12.0-160000.27.1 SUSE-SU-2026:20873-1, SUSE-SU-2026:20838-1
SLE Micro 6.1 kernel-default-base 6.4.0-40.1.21.17 SUSE-SU-2026:20667-1
SLE Micro 6.1 kernel-rt +4 6.4.0-40.1 SUSE-SU-2026:20876-1, SUSE-SU-2026:20667-1
SLE Micro 6.0 kernel-default-base 6.4.0-40.1.21.17 SUSE-SU-2026:20720-1
SLE Micro 6.0 kernel-rt +4 6.4.0-40.1 SUSE-SU-2026:20845-1, SUSE-SU-2026:20720-1
SLE Live Patching 15 SP7 kernel-default 6.4.0-150700.53.34.1 SUSE-SU-2026:1081-1
SLE Live Patching 15 SP7 kernel-livepatch-SLE15-SP7-RT_Update_10 1-150700.1.3.1 SUSE-SU-2026:0962-1
SLE Live Patching 15 SP7 kernel-livepatch-SLE15-SP7_Update_10 1-150700.15.3.1 SUSE-SU-2026:1081-1
SLE Live Patching 12 SP5 kernel-default 4.12.14-122.296.1 SUSE-SU-2026:1078-1
SLE Live Patching 12 SP5 kgraft-patch-SLE12-SP5_Update_78 1-8.3.1 SUSE-SU-2026:1078-1
SUSE Real Time Module 15 SP7 kernel-rt +2 6.4.0-150700.7.34.1 SUSE-SU-2026:0962-1
ReleasePackageFixed inAdvisory
openSUSE Leap 16.0 kernel-default-base 6.12.0-160000.27.1.160000.2.8 openSUSE-SU-2026:20416-1
openSUSE Leap 16.0 kernel-rt +11 6.12.0-160000.27.1 openSUSE-SU-2026:20416-1

Amazon Linux

ReleasePackageFixed inAdvisory
Amazon Linux 2023 kernel-livepatch-6.12.68-92.122 +1 1:1.0-0.amzn2023 ALAS2023-2026-1468, ALAS2023-2026-1455
Amazon Linux 2023 perf +14 1:6.1.163-186.299.amzn2023 ALAS2023-2026-1468
Amazon Linux 2023 perf6.12 +14 1:6.12.68-92.122.amzn2023 ALAS2023-2026-1455

Azure Linux

ReleasePackageFixed inAdvisory
Azure Linux 3 kernel 6.6.126.1-1 —

Oracle Linux

ReleasePackageFixed inAdvisory
Oracle Linux 9 kernel-uek +34 6.12.0-200.74.27.el10uek ELSA-2026-50372, ELSA-2026-50232, ELSA-2026-50160

Advisories 50

References