CVE-2025-38678: netfilter: nf_tables: reject duplicate device on updates

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-09-03 · updated 2026-10-19

Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_tables: reject duplicate device on updates A chain/flowtable update with duplicated devices in the same batch is possible. Unfortunately, netdev event path only removes the first device that is found, leaving unregistered the hook of the duplicated device. Check if a duplicated device exists in the transaction batch, bail out with EEXIST in such case. WARNING is hit when unregistering the hook: [49042.221275] WARNING: CPU: 4 PID: 8425 at net/netfilter/core.c:340 nf_hook_entry_head+0xaa/0x150 [49042.221375] CPU: 4 UID: 0 PID: 8425 Comm: nft Tainted: G S 6.16.0+ #170 PREEMPT(full) [...] [49042.221382] RIP: 0010:nf_hook_entry_head+0xaa/0x150

Affected products

Linux kernel: from 5.8 before 6.6.117; from 6.7 before 6.12.59; from 6.13 before 6.16.2; 6.17-rc1 — fixed in 6.12.59, 6.16.2, 6.6.117

How to fix

Upgrade to a fixed version: Linux kernel 6.12.59, 6.16.2, 6.6.117. Check the vendor advisory for mitigations.

References

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