CVE Vulnerabilities

CVE-2025-39894

Published: Oct 01, 2025 | Modified: Jan 16, 2026
CVSS 3.x
5.5
MEDIUM
Source:
NVD
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CVSS 2.x
RedHat/V2
RedHat/V3
6.2 MODERATE
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Ubuntu
MEDIUM
root.io logo minimus.io logo echo.ai logo

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

netfilter: br_netfilter: do not check confirmed bit in br_nf_local_in() after confirm

When send a broadcast packet to a tap device, which was added to a bridge, br_nf_local_in() is called to confirm the conntrack. If another conntrack with the same hash value is added to the hash table, which can be triggered by a normal packet to a non-bridge device, the below warning may happen.

————[ cut here ]———— WARNING: CPU: 1 PID: 96 at net/bridge/br_netfilter_hooks.c:632 br_nf_local_in+0x168/0x200 CPU: 1 UID: 0 PID: 96 Comm: tap_send Not tainted 6.17.0-rc2-dirty #44 PREEMPT(voluntary) RIP: 0010:br_nf_local_in+0x168/0x200 Call Trace: nf_hook_slow+0x3e/0xf0 br_pass_frame_up+0x103/0x180 br_handle_frame_finish+0x2de/0x5b0 br_nf_hook_thresh+0xc0/0x120 br_nf_pre_routing_finish+0x168/0x3a0 br_nf_pre_routing+0x237/0x5e0 br_handle_frame+0x1ec/0x3c0 __netif_receive_skb_core+0x225/0x1210 __netif_receive_skb_one_core+0x37/0xa0 netif_receive_skb+0x36/0x160 tun_get_user+0xa54/0x10c0 tun_chr_write_iter+0x65/0xb0 vfs_write+0x305/0x410 ksys_write+0x60/0xd0 do_syscall_64+0xa4/0x260 entry_SYSCALL_64_after_hwframe+0x77/0x7f —[ end trace 0000000000000000 ]—

To solve the hash conflict, nf_ct_resolve_clash() try to merge the conntracks, and update skb->_nfct. However, br_nf_local_in() still use the old ct from local variable nfct after confirm(), which leads to this warning.

If confirm() does not insert the conntrack entry and return NF_DROP, the warning may also occur. There is no need to reserve the WARN_ON_ONCE, just remove it.

Affected Software

NameVendorStart VersionEnd Version
Linux_kernelLinux5.15.151 (including)5.15.192 (excluding)
Linux_kernelLinux6.1.81 (including)6.1.151 (excluding)
Linux_kernelLinux6.6.21 (including)6.6.105 (excluding)
Linux_kernelLinux6.7.9 (including)6.8 (excluding)
Linux_kernelLinux6.8.1 (including)6.12.46 (excluding)
Linux_kernelLinux6.13 (including)6.16.6 (excluding)
Linux_kernelLinux6.8 (including)6.8 (including)
Linux_kernelLinux6.8-rc7 (including)6.8-rc7 (including)
Linux_kernelLinux6.17-rc1 (including)6.17-rc1 (including)
Linux_kernelLinux6.17-rc2 (including)6.17-rc2 (including)
Linux_kernelLinux6.17-rc3 (including)6.17-rc3 (including)
Linux_kernelLinux6.17-rc4 (including)6.17-rc4 (including)
LinuxUbuntujammy*
LinuxUbuntunoble*
LinuxUbuntuplucky*
LinuxUbuntuupstream*
Linux-allwinner-5.19Ubuntujammy*
Linux-allwinner-5.19Ubuntuupstream*
Linux-awsUbuntujammy*
Linux-awsUbuntunoble*
Linux-awsUbuntuplucky*
Linux-awsUbuntuupstream*
Linux-aws-5.0Ubuntubionic*
Linux-aws-5.0Ubuntuesm-infra/bionic*
Linux-aws-5.0Ubuntuupstream*
Linux-aws-5.11Ubuntuesm-infra/focal*
Linux-aws-5.11Ubuntufocal*
Linux-aws-5.11Ubuntuupstream*
Linux-aws-5.13Ubuntuesm-infra/focal*
Linux-aws-5.13Ubuntufocal*
Linux-aws-5.13Ubuntuupstream*
Linux-aws-5.15Ubuntuesm-infra/focal*
Linux-aws-5.15Ubuntufocal*
Linux-aws-5.15Ubuntuupstream*
Linux-aws-5.19Ubuntujammy*
Linux-aws-5.19Ubuntuupstream*
Linux-aws-5.3Ubuntubionic*
Linux-aws-5.3Ubuntuesm-infra/bionic*
Linux-aws-5.3Ubuntuupstream*
Linux-aws-5.4Ubuntuupstream*
Linux-aws-5.8Ubuntuesm-infra/focal*
Linux-aws-5.8Ubuntufocal*
Linux-aws-5.8Ubuntuupstream*
Linux-aws-6.14Ubuntunoble*
Linux-aws-6.14Ubuntuupstream*
Linux-aws-6.2Ubuntujammy*
Linux-aws-6.2Ubuntuupstream*
Linux-aws-6.5Ubuntujammy*
Linux-aws-6.5Ubuntuupstream*
Linux-aws-6.8Ubuntujammy*
Linux-aws-6.8Ubuntuupstream*
Linux-aws-fipsUbuntufips-updates/jammy*
Linux-aws-fipsUbuntufips-updates/noble*
Linux-aws-fipsUbuntutrusty*
Linux-aws-fipsUbuntuupstream*
Linux-aws-fipsUbuntuxenial*
Linux-aws-hweUbuntuupstream*
Linux-azureUbuntubionic*
Linux-azureUbuntuesm-infra/bionic*
Linux-azureUbuntujammy*
Linux-azureUbuntunoble*
Linux-azureUbuntuplucky*
Linux-azureUbuntuupstream*
Linux-azure-4.15Ubuntuupstream*
Linux-azure-5.11Ubuntuesm-infra/focal*
Linux-azure-5.11Ubuntufocal*
Linux-azure-5.11Ubuntuupstream*
Linux-azure-5.13Ubuntuesm-infra/focal*
Linux-azure-5.13Ubuntufocal*
Linux-azure-5.13Ubuntuupstream*
Linux-azure-5.15Ubuntuesm-infra/focal*
Linux-azure-5.15Ubuntufocal*
Linux-azure-5.15Ubuntuupstream*
Linux-azure-5.19Ubuntujammy*
Linux-azure-5.19Ubuntuupstream*
Linux-azure-5.3Ubuntubionic*
Linux-azure-5.3Ubuntuesm-infra/bionic*
Linux-azure-5.3Ubuntuupstream*
Linux-azure-5.4Ubuntuupstream*
Linux-azure-5.8Ubuntuesm-infra/focal*
Linux-azure-5.8Ubuntufocal*
Linux-azure-5.8Ubuntuupstream*
Linux-azure-6.11Ubuntunoble*
Linux-azure-6.11Ubuntuupstream*
Linux-azure-6.14Ubuntunoble*
Linux-azure-6.14Ubuntuupstream*
Linux-azure-6.2Ubuntujammy*
Linux-azure-6.2Ubuntuupstream*
Linux-azure-6.5Ubuntujammy*
Linux-azure-6.5Ubuntuupstream*
Linux-azure-6.8Ubuntujammy*
Linux-azure-6.8Ubuntuupstream*
Linux-azure-edgeUbuntubionic*
Linux-azure-edgeUbuntuesm-infra/bionic*
Linux-azure-edgeUbuntuupstream*
Linux-azure-fdeUbuntuesm-infra/focal*
Linux-azure-fdeUbuntufocal*
Linux-azure-fdeUbuntujammy*
Linux-azure-fdeUbuntunoble*
Linux-azure-fdeUbuntuplucky*
Linux-azure-fdeUbuntuupstream*
Linux-azure-fde-5.15Ubuntuupstream*
Linux-azure-fde-5.19Ubuntujammy*
Linux-azure-fde-5.19Ubuntuupstream*
Linux-azure-fde-6.14Ubuntunoble*
Linux-azure-fde-6.14Ubuntuupstream*
Linux-azure-fde-6.2Ubuntujammy*
Linux-azure-fde-6.2Ubuntuupstream*
Linux-azure-fde-6.8Ubuntujammy*
Linux-azure-fde-6.8Ubuntuupstream*
Linux-azure-fipsUbuntufips-updates/jammy*
Linux-azure-fipsUbuntufips-updates/noble*
Linux-azure-fipsUbuntutrusty*
Linux-azure-fipsUbuntuupstream*
Linux-azure-fipsUbuntuxenial*
Linux-azure-nvidiaUbuntunoble*
Linux-azure-nvidiaUbuntuupstream*
Linux-azure-nvidia-6.14Ubuntunoble*
Linux-azure-nvidia-6.14Ubuntuupstream*
Linux-bluefieldUbuntubluefield/jammy*
Linux-bluefieldUbuntuupstream*
Linux-fipsUbuntufips-updates/jammy*
Linux-fipsUbuntufips-updates/noble*
Linux-fipsUbuntuupstream*
Linux-gcpUbuntubionic*
Linux-gcpUbuntuesm-infra/bionic*
Linux-gcpUbuntujammy*
Linux-gcpUbuntunoble*
Linux-gcpUbuntuplucky*
Linux-gcpUbuntuupstream*
Linux-gcp-4.15Ubuntuupstream*
Linux-gcp-5.11Ubuntuesm-infra/focal*
Linux-gcp-5.11Ubuntufocal*
Linux-gcp-5.11Ubuntuupstream*
Linux-gcp-5.13Ubuntuesm-infra/focal*
Linux-gcp-5.13Ubuntufocal*
Linux-gcp-5.13Ubuntuupstream*
Linux-gcp-5.15Ubuntuesm-infra/focal*
Linux-gcp-5.15Ubuntufocal*
Linux-gcp-5.15Ubuntuupstream*
Linux-gcp-5.19Ubuntujammy*
Linux-gcp-5.19Ubuntuupstream*
Linux-gcp-5.3Ubuntubionic*
Linux-gcp-5.3Ubuntuesm-infra/bionic*
Linux-gcp-5.3Ubuntuupstream*
Linux-gcp-5.4Ubuntuupstream*
Linux-gcp-5.8Ubuntuesm-infra/focal*
Linux-gcp-5.8Ubuntufocal*
Linux-gcp-5.8Ubuntuupstream*
Linux-gcp-6.11Ubuntunoble*
Linux-gcp-6.11Ubuntuupstream*
Linux-gcp-6.14Ubuntunoble*
Linux-gcp-6.14Ubuntuupstream*
Linux-gcp-6.2Ubuntujammy*
Linux-gcp-6.2Ubuntuupstream*
Linux-gcp-6.5Ubuntujammy*
Linux-gcp-6.5Ubuntuupstream*
Linux-gcp-6.8Ubuntujammy*
Linux-gcp-6.8Ubuntuupstream*
Linux-gcp-fipsUbuntufips-updates/jammy*
Linux-gcp-fipsUbuntufips-updates/noble*
Linux-gcp-fipsUbuntutrusty*
Linux-gcp-fipsUbuntuupstream*
Linux-gcp-fipsUbuntuxenial*
Linux-gkeUbuntuesm-infra/focal*
Linux-gkeUbuntufocal*
Linux-gkeUbuntujammy*
Linux-gkeUbuntunoble*
Linux-gkeUbuntuupstream*
Linux-gkeUbuntuxenial*
Linux-gke-4.15Ubuntubionic*
Linux-gke-4.15Ubuntuesm-infra/bionic*
Linux-gke-4.15Ubuntuupstream*
Linux-gke-5.15Ubuntuesm-infra/focal*
Linux-gke-5.15Ubuntufocal*
Linux-gke-5.15Ubuntuupstream*
Linux-gke-5.4Ubuntubionic*
Linux-gke-5.4Ubuntuesm-infra/bionic*
Linux-gke-5.4Ubuntuupstream*
Linux-gkeopUbuntuesm-infra/focal*
Linux-gkeopUbuntufocal*
Linux-gkeopUbuntujammy*
Linux-gkeopUbuntunoble*
Linux-gkeopUbuntuupstream*
Linux-gkeop-5.15Ubuntuesm-infra/focal*
Linux-gkeop-5.15Ubuntufocal*
Linux-gkeop-5.15Ubuntuupstream*
Linux-gkeop-5.4Ubuntubionic*
Linux-gkeop-5.4Ubuntuesm-infra/bionic*
Linux-gkeop-5.4Ubuntuupstream*
Linux-hweUbuntubionic*
Linux-hweUbuntuesm-infra/bionic*
Linux-hweUbuntuupstream*
Linux-hwe-5.11Ubuntuesm-infra/focal*
Linux-hwe-5.11Ubuntufocal*
Linux-hwe-5.11Ubuntuupstream*
Linux-hwe-5.13Ubuntuesm-infra/focal*
Linux-hwe-5.13Ubuntufocal*
Linux-hwe-5.13Ubuntuupstream*
Linux-hwe-5.15Ubuntuesm-infra/focal*
Linux-hwe-5.15Ubuntufocal*
Linux-hwe-5.15Ubuntuupstream*
Linux-hwe-5.19Ubuntujammy*
Linux-hwe-5.19Ubuntuupstream*
Linux-hwe-5.4Ubuntuupstream*
Linux-hwe-5.8Ubuntuesm-infra/focal*
Linux-hwe-5.8Ubuntufocal*
Linux-hwe-5.8Ubuntuupstream*
Linux-hwe-6.11Ubuntunoble*
Linux-hwe-6.11Ubuntuupstream*
Linux-hwe-6.14Ubuntunoble*
Linux-hwe-6.14Ubuntuupstream*
Linux-hwe-6.2Ubuntujammy*
Linux-hwe-6.2Ubuntuupstream*
Linux-hwe-6.5Ubuntujammy*
Linux-hwe-6.5Ubuntuupstream*
Linux-hwe-6.8Ubuntujammy*
Linux-hwe-6.8Ubuntuupstream*
Linux-hwe-edgeUbuntubionic*
Linux-hwe-edgeUbuntuesm-infra/bionic*
Linux-hwe-edgeUbuntuesm-infra/xenial*
Linux-hwe-edgeUbuntuupstream*
Linux-hwe-edgeUbuntuxenial*
Linux-ibmUbuntujammy*
Linux-ibmUbuntunoble*
Linux-ibmUbuntuupstream*
Linux-ibm-5.15Ubuntuesm-infra/focal*
Linux-ibm-5.15Ubuntufocal*
Linux-ibm-5.15Ubuntuupstream*
Linux-ibm-5.4Ubuntuupstream*
Linux-ibm-6.8Ubuntujammy*
Linux-ibm-6.8Ubuntuupstream*
Linux-intelUbuntunoble*
Linux-intelUbuntuupstream*
Linux-intel-5.13Ubuntuesm-infra/focal*
Linux-intel-5.13Ubuntufocal*
Linux-intel-5.13Ubuntuupstream*
Linux-intel-iot-realtimeUbuntujammy*
Linux-intel-iot-realtimeUbunturealtime/jammy*
Linux-intel-iot-realtimeUbuntuupstream*
Linux-intel-iotgUbuntujammy*
Linux-intel-iotgUbuntuupstream*
Linux-intel-iotg-5.15Ubuntuesm-infra/focal*
Linux-intel-iotg-5.15Ubuntufocal*
Linux-intel-iotg-5.15Ubuntuupstream*
Linux-iotUbuntuupstream*
Linux-kvmUbuntujammy*
Linux-kvmUbuntuupstream*
Linux-lowlatencyUbuntujammy*
Linux-lowlatencyUbuntunoble*
Linux-lowlatencyUbuntuupstream*
Linux-lowlatency-hwe-5.15Ubuntuesm-infra/focal*
Linux-lowlatency-hwe-5.15Ubuntufocal*
Linux-lowlatency-hwe-5.15Ubuntuupstream*
Linux-lowlatency-hwe-5.19Ubuntujammy*
Linux-lowlatency-hwe-5.19Ubuntuupstream*
Linux-lowlatency-hwe-6.11Ubuntunoble*
Linux-lowlatency-hwe-6.11Ubuntuupstream*
Linux-lowlatency-hwe-6.2Ubuntujammy*
Linux-lowlatency-hwe-6.2Ubuntuupstream*
Linux-lowlatency-hwe-6.5Ubuntujammy*
Linux-lowlatency-hwe-6.5Ubuntuupstream*
Linux-lowlatency-hwe-6.8Ubuntujammy*
Linux-lowlatency-hwe-6.8Ubuntuupstream*
Linux-lts-xenialUbuntuupstream*
Linux-nvidiaUbuntujammy*
Linux-nvidiaUbuntunoble*
Linux-nvidiaUbuntuupstream*
Linux-nvidia-6.11Ubuntunoble*
Linux-nvidia-6.11Ubuntuupstream*
Linux-nvidia-6.2Ubuntujammy*
Linux-nvidia-6.2Ubuntuupstream*
Linux-nvidia-6.5Ubuntujammy*
Linux-nvidia-6.5Ubuntuupstream*
Linux-nvidia-6.8Ubuntujammy*
Linux-nvidia-6.8Ubuntuupstream*
Linux-nvidia-lowlatencyUbuntunoble*
Linux-nvidia-lowlatencyUbuntuupstream*
Linux-nvidia-tegraUbuntujammy*
Linux-nvidia-tegraUbuntunoble*
Linux-nvidia-tegraUbuntuupstream*
Linux-nvidia-tegra-5.15Ubuntuesm-infra/focal*
Linux-nvidia-tegra-5.15Ubuntufocal*
Linux-nvidia-tegra-5.15Ubuntuupstream*
Linux-nvidia-tegra-igxUbuntujammy*
Linux-nvidia-tegra-igxUbuntuupstream*
Linux-oemUbuntubionic*
Linux-oemUbuntuesm-infra/bionic*
Linux-oemUbuntuupstream*
Linux-oemUbuntuxenial*
Linux-oem-5.10Ubuntuesm-infra/focal*
Linux-oem-5.10Ubuntufocal*
Linux-oem-5.10Ubuntuupstream*
Linux-oem-5.13Ubuntuesm-infra/focal*
Linux-oem-5.13Ubuntufocal*
Linux-oem-5.13Ubuntuupstream*
Linux-oem-5.14Ubuntuesm-infra/focal*
Linux-oem-5.14Ubuntufocal*
Linux-oem-5.14Ubuntuupstream*
Linux-oem-5.17Ubuntujammy*
Linux-oem-5.17Ubuntuupstream*
Linux-oem-5.6Ubuntuesm-infra/focal*
Linux-oem-5.6Ubuntufocal*
Linux-oem-5.6Ubuntuupstream*
Linux-oem-6.0Ubuntujammy*
Linux-oem-6.0Ubuntuupstream*
Linux-oem-6.1Ubuntujammy*
Linux-oem-6.1Ubuntuupstream*
Linux-oem-6.11Ubuntunoble*
Linux-oem-6.11Ubuntuupstream*
Linux-oem-6.14Ubuntunoble*
Linux-oem-6.14Ubuntuupstream*
Linux-oem-6.17Ubuntuupstream*
Linux-oem-6.5Ubuntujammy*
Linux-oem-6.5Ubuntuupstream*
Linux-oem-6.8Ubuntunoble*
Linux-oem-6.8Ubuntuupstream*
Linux-oracleUbuntujammy*
Linux-oracleUbuntunoble*
Linux-oracleUbuntuplucky*
Linux-oracleUbuntuupstream*
Linux-oracle-5.0Ubuntubionic*
Linux-oracle-5.0Ubuntuesm-infra/bionic*
Linux-oracle-5.0Ubuntuupstream*
Linux-oracle-5.11Ubuntuesm-infra/focal*
Linux-oracle-5.11Ubuntufocal*
Linux-oracle-5.11Ubuntuupstream*
Linux-oracle-5.13Ubuntuesm-infra/focal*
Linux-oracle-5.13Ubuntufocal*
Linux-oracle-5.13Ubuntuupstream*
Linux-oracle-5.15Ubuntuesm-infra/focal*
Linux-oracle-5.15Ubuntufocal*
Linux-oracle-5.15Ubuntuupstream*
Linux-oracle-5.3Ubuntubionic*
Linux-oracle-5.3Ubuntuesm-infra/bionic*
Linux-oracle-5.3Ubuntuupstream*
Linux-oracle-5.4Ubuntuupstream*
Linux-oracle-5.8Ubuntuesm-infra/focal*
Linux-oracle-5.8Ubuntufocal*
Linux-oracle-5.8Ubuntuupstream*
Linux-oracle-6.14Ubuntunoble*
Linux-oracle-6.14Ubuntuupstream*
Linux-oracle-6.5Ubuntujammy*
Linux-oracle-6.5Ubuntuupstream*
Linux-oracle-6.8Ubuntujammy*
Linux-oracle-6.8Ubuntuupstream*
Linux-raspiUbuntujammy*
Linux-raspiUbuntunoble*
Linux-raspiUbuntuplucky*
Linux-raspiUbuntuupstream*
Linux-raspi-5.4Ubuntuupstream*
Linux-raspi-realtimeUbuntunoble*
Linux-raspi-realtimeUbunturealtime/noble*
Linux-raspi-realtimeUbuntuupstream*
Linux-raspi2Ubuntubionic*
Linux-raspi2Ubuntuesm-infra/focal*
Linux-raspi2Ubuntufocal*
Linux-raspi2Ubuntuupstream*
Linux-raspi2Ubuntuxenial*
Linux-realtimeUbuntujammy*
Linux-realtimeUbuntunoble*
Linux-realtimeUbuntuplucky*
Linux-realtimeUbunturealtime/jammy*
Linux-realtimeUbunturealtime/noble*
Linux-realtimeUbuntuupstream*
Linux-realtime-6.14Ubunturealtime/noble*
Linux-realtime-6.14Ubuntuupstream*
Linux-realtime-6.8Ubunturealtime/jammy*
Linux-realtime-6.8Ubuntuupstream*
Linux-riscvUbuntuesm-infra/focal*
Linux-riscvUbuntufocal*
Linux-riscvUbuntujammy*
Linux-riscvUbuntunoble*
Linux-riscvUbuntuplucky*
Linux-riscvUbuntuupstream*
Linux-riscv-5.11Ubuntuesm-infra/focal*
Linux-riscv-5.11Ubuntufocal*
Linux-riscv-5.11Ubuntuupstream*
Linux-riscv-5.15Ubuntuesm-infra/focal*
Linux-riscv-5.15Ubuntufocal*
Linux-riscv-5.15Ubuntuupstream*
Linux-riscv-5.19Ubuntujammy*
Linux-riscv-5.19Ubuntuupstream*
Linux-riscv-5.8Ubuntuesm-infra/focal*
Linux-riscv-5.8Ubuntufocal*
Linux-riscv-5.8Ubuntuupstream*
Linux-riscv-6.14Ubuntunoble*
Linux-riscv-6.14Ubuntuupstream*
Linux-riscv-6.5Ubuntujammy*
Linux-riscv-6.5Ubuntuupstream*
Linux-riscv-6.8Ubuntujammy*
Linux-riscv-6.8Ubuntuupstream*
Linux-starfive-5.19Ubuntujammy*
Linux-starfive-5.19Ubuntuupstream*
Linux-starfive-6.2Ubuntujammy*
Linux-starfive-6.2Ubuntuupstream*
Linux-starfive-6.5Ubuntujammy*
Linux-starfive-6.5Ubuntuupstream*
Linux-xilinxUbuntunoble*
Linux-xilinxUbuntuplucky*
Linux-xilinxUbuntuupstream*
Linux-xilinx-zynqmpUbuntujammy*
Linux-xilinx-zynqmpUbuntuupstream*

References