🛡️ UBUNTU-CVE-2025-68206
⚪ Unknown ✅ No Known Exploit OSV
N/A
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: nft_ct: add seqadj extension for natted connections Sequence adjustment may be required for FTP traffic with PASV/EPSV modes. due to need to re-write packet payload (IP, port) on the ftp control connection. This can require changes to the TCP length and expected seq / ack_seq. The easiest way to reproduce this issue is with PASV mode. Example ruleset: table inet ftp_nat { ct helper ftp_helper { type "ftp" protocol tcp l3proto inet } chain prerouting { type filter hook prerouting priority 0; policy accept; tcp dport 21 ct state new ct helper set "ftp_helper" } } table ip nat { chain prerouting { type nat hook prerouting priority -100; policy accept; tcp dport 21 dnat ip prefix to ip daddr map { 192.168.100.1 : 192.168.13.2/32 } } chain postrouting { type nat hook postrouting priority 100 ; policy accept; tcp sport 21 snat ip prefix to ip saddr map { 192.168.13.2 : 192.168.100.1/32 } } } Note that the ftp helper gets assigned *after* the dnat setup. The inverse (nat after helper assign) is handled by an existing check in nf_nat_setup_info() and will not show the problem. Topoloy: +-------------------+ +----------------------------------+ | FTP: 192.168.13.2 | | NAT: 192.168.13.3, 192.168.100.1 | +-------------------+ +----------------------------------+ | +-----------------------+ | Client: 192.168.100.2 | +-----------------------+ ftp nat changes do not work as expected in this case: Connected to 192.168.100.1. [..] ftp> epsv EPSV/EPRT on IPv4 off. ftp> ls 227 Entering passive mode (192,168,100,1,209,129). 421 Service not available, remote server has closed connection. Kernel logs: Missing nfct_seqadj_ext_add() setup call WARNING: CPU: 1 PID: 0 at net/netfilter/nf_conntrack_seqadj.c:41 [..] __nf_nat_mangle_tcp_packet+0x100/0x160 [nf_nat] nf_nat_ftp+0x142/0x280 [nf_nat_ftp] help+0x4d1/0x880 [nf_conntrack_ftp] nf_confirm+0x122/0x2e0 [nf_conntrack] nf_hook_slow+0x3c/0xb0 .. Fix this by adding the required extension when a conntrack helper is assigned to a connection that has a nat binding.

Details

Severity Unknown
CVSS Score N/A
CVSS Vector N/A
CWE N/A
Public Exploit ✅ No
Source OSV
Published 2025-12-16
Updated 2026-06-15
Modified 2026-06-08
Fix URL N/A

Affected Packages

Software From version Fixed in
linux 6.17.0-14.14
linux-allwinner-5.19
linux-aws 6.17.0-1007.7
linux-aws-5.0
linux-aws-5.11
linux-aws-5.13
linux-aws-5.15
linux-aws-5.19
linux-aws-5.3
linux-aws-5.4
linux-aws-5.8
linux-aws-6.14
linux-aws-6.17 6.17.0-1007.7~24.04.1
linux-aws-6.2
linux-aws-6.5
linux-aws-6.8 6.8.0-1052.55~22.04.1
linux-aws-fips 6.8.0-1052.55+fips1
linux-aws-hwe
linux-azure 6.17.0-1008.8
linux-azure-4.15
linux-azure-5.11
linux-azure-5.13
linux-azure-5.15
linux-azure-5.19
linux-azure-5.3
linux-azure-5.4
linux-azure-5.8
linux-azure-6.11
linux-azure-6.14
linux-azure-6.2
linux-azure-6.5
linux-azure-6.8
linux-azure-edge
linux-azure-fde
linux-azure-fde-5.19
linux-azure-fde-6.14
linux-azure-fde-6.17
linux-azure-fde-6.2
linux-azure-fde-6.8
linux-azure-fips 6.8.0-1053.59+fips1
linux-azure-nvidia
linux-azure-nvidia-6.14
linux-bluefield
linux-fips 6.8.0-110.110+fips2
linux-gcp 6.17.0-1007.7
linux-gcp-4.15
linux-gcp-5.11
linux-gcp-5.13
linux-gcp-5.15
linux-gcp-5.19
linux-gcp-5.3
linux-gcp-5.4
linux-gcp-5.8
linux-gcp-6.11
linux-gcp-6.14
linux-gcp-6.17 6.17.0-1008.8~24.04.1
linux-gcp-6.2
linux-gcp-6.5
linux-gcp-6.8 6.8.0-1054.57~22.04.1
linux-gcp-fips 6.8.0-1054.57+fips1
linux-gke 6.8.0-1050.56
linux-gke-4.15
linux-gke-5.15
linux-gke-5.4
linux-gkeop 6.8.0-1037.40
linux-gkeop-5.15
linux-gkeop-5.4
linux-hwe
linux-hwe-5.11
linux-hwe-5.13
linux-hwe-5.15
linux-hwe-5.19
linux-hwe-5.4
linux-hwe-5.8
linux-hwe-6.11
linux-hwe-6.14
linux-hwe-6.2
linux-hwe-6.5
linux-hwe-6.8 6.8.0-110.110~22.04.1
linux-hwe-edge
linux-ibm 6.8.0-1051.51
linux-ibm-5.15
linux-ibm-5.4
linux-ibm-6.8 6.8.0-1051.51~22.04.1
linux-intel-5.13
linux-intel-iot-realtime
linux-intel-iotg
linux-intel-iotg-5.15
linux-iot
linux-kvm
linux-lowlatency 6.8.0-110.110.1
linux-lowlatency-hwe-5.15
linux-lowlatency-hwe-5.19
linux-lowlatency-hwe-6.11
linux-lowlatency-hwe-6.2
linux-lowlatency-hwe-6.5
linux-lowlatency-hwe-6.8 6.8.0-110.110.1~22.04.1
linux-nvidia 6.8.0-1051.54
linux-nvidia-6.11
linux-nvidia-6.17 6.17.0-1008.8
linux-nvidia-6.2
linux-nvidia-6.5
linux-nvidia-6.8 6.8.0-1051.54~22.04.1
linux-nvidia-lowlatency 6.8.0-1051.54.1
linux-nvidia-tegra 6.8.0-1022.22
linux-nvidia-tegra-5.15
linux-nvidia-tegra-igx
linux-oem
linux-oem-5.10
linux-oem-5.13
linux-oem-5.14
linux-oem-5.17
linux-oem-5.6
linux-oem-6.0
linux-oem-6.1
linux-oem-6.11
linux-oem-6.14
linux-oem-6.17 6.17.0-1011.11
linux-oem-6.5
linux-oem-6.8
linux-oracle 6.17.0-1007.7
linux-oracle-5.0
linux-oracle-5.11
linux-oracle-5.13
linux-oracle-5.15
linux-oracle-5.3
linux-oracle-5.4
linux-oracle-5.8
linux-oracle-6.14
linux-oracle-6.17 6.17.0-1007.7~24.04.1
linux-oracle-6.5
linux-oracle-6.8 6.8.0-1049.50~22.04.1
linux-raspi 6.17.0-1008.8
linux-raspi-5.4
linux-raspi-realtime 6.8.0-2042.43
linux-raspi2
linux-realtime 6.17.0-1006.7
linux-realtime-6.14
linux-realtime-6.17 6.17.0-1006.7~24.04.1
linux-realtime-6.8 6.8.1-1047.48~22.04.1
linux-riscv 6.17.0-14.14.1
linux-riscv-5.11
linux-riscv-5.15
linux-riscv-5.19
linux-riscv-5.8
linux-riscv-6.14
linux-riscv-6.5
linux-riscv-6.8 6.8.0-110.110~22.04.1
linux-starfive-5.19
linux-starfive-6.2
linux-starfive-6.5
linux-xilinx 6.8.0-1028.29
linux-xilinx-zynqmp

References

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