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CVE-2026-46324
netfilter: nf_tables: use list_del_rcu for netlink hooks
Published 2026-06-09 (4 months ago) by the Linux kernel CNA. Subsystem net/netfilter. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-46324 in every release this site tracks, and what each one means in practice. Every status below is the one the Debian Security Team publishes for this CVE. source
| Release | Status | Version | What this means |
|---|---|---|---|
| Debian 12bookworm | vulnerable | 6.1.190-1 | No fix published anywhere yet, neither in Debian nor upstream for the series bookworm tracks. Watch the Debian tracker page for this CVE. Advisories for bookworm have historically landed a median of 23 days after publication. |
| Debian 13trixie | vulnerable | 6.12.113-1 | No fix published anywhere yet, neither in Debian nor upstream for the series trixie tracks. Watch the Debian tracker page for this CVE. Advisories for trixie have historically landed a median of 11 days after publication. |
| Debian 14forky | fixed | 7.0.10-1 | Update the kernel and reboot. Fixed in 7.0.10-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.0.10-1 | Update the kernel and reboot. Fixed in 7.0.10-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
nft_netdev_unregister_hooks and __nft_unregister_flowtable_net_hooks need to use list_del_rcu(), this list can be walked by concurrent dumpers. Add a new helper and use it consistently.
Where it lives
The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.
net/netfilter/nf_tables_api.c
- What this is
- NETFILTERMAINTAINERS section matched on net/netfilter/ · netfilter-devel@vger.kernel.org · Maintained
- Kernel module
- nf_tables
Check it on the machine
grep -wE 'CONFIG_NETFILTER|CONFIG_NF_TABLES' /boot/config-$(uname -r)Reads the booted kernel's own configuration, on the machine and nowhere else. =y is built in, =m is a module, and an is not set line means the code is not there.
lsmod | grep -w nf_tablesPrints a line if that module is loaded right now, and nothing if it is not. One that is not loaded can still be loaded later by anything that needs it.
Show whether Debian builds this, per release
Debian builds this as a loadable module. Every release below compiles it as a module on every flavour, so whether the code is in the running kernel depends on whether that module is loaded.
- bookworm, trixie, forky, sidm
- m
- a loadable module on every flavour - check lsmod, can be blacklisted
- Build switches
- CONFIG_NETFILTER, CONFIG_NF_TABLES
- Reads as
- all on means the file is compiled; any one off means it is not.
From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS kbuild Makefiles Debian linux-config packages
Signals
- Published
- 2026-06-09 (4 months ago)source
- CVSS
- 7.8 high
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.12%, higher than 1.6% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- net/netfilter
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 5.19 | 6.18.33 | 0bd93ce4f3c3 |
| 5.19 | 7.0.10 | 0f33e8ad6ac5 |
| 5.19 | 7.1 | f3224ee463f8 |
| 4.19.316 | 0 | 0 |
| 5.4.262 | 0 | 0 |
| 5.10.198 | 0 | 0 |
| 5.15.45 | 0 | 0 |
| 5.17.13 | 0 | 0 |
| 5.18.2 | 0 | 0 |
Why the CNA scored it this way
Quoted from the kernel CNA's own scoring file, word for word. A highlighted metric carries the most severe value CVSS v3.1 defines for it, which is what pushes the score up. source
- AV:LAttack vector, local
- The bug is in nf_tables netdev hook teardown reached only via Netfilter netlink (nft) syscalls—chain/flowtable updates, dumps, netns teardown, and netlink socket release—not from remote packet handling alone. Per kernel guidance, nftables/netfilter is Local (L).
- AC:LAttack complexity, low
- Exploitation is a race between hook-list removal (`list_del()` + RCU free) and concurrent RCU walkers (`nft_dump_basechain_hook_list`, flowtable dump, or packet-path `list_for_each_entry_rcu`). An attacker with CAP_NET_ADMIN can drive both sides concurrently (e.g., one thread dumping chains/flowtables while another deletes hooks or tears down the netns).
- PR:LPrivileges required, low
- All nf_tables netlink operations are gated by `netlink_net_capable(skb, CAP_NET_ADMIN)` in `nfnetlink_rcv()`. CAP_NET_ADMIN is obtainable by an unprivileged user via user+network namespaces (`unshare -Urn`), not real init-namespace root.
- UI:NUser interaction, none
- No victim interaction is required; the attacker triggers hook teardown and concurrent dumps or traffic entirely through their own netlink sockets and namespace lifecycle.
- S:UScope, unchanged
- Impact is confined to kernel memory corruption and privilege escalation within the same kernel security domain; it does not inherently cross VM, container, or IOMMU boundaries.
- C:HConfidentiality impact, high
- Using `list_del()` instead of `list_del_rcu()` on lists walked under `rcu_read_lock()` is a use-after-free/list-corruption bug; concurrent dumpers dereference `nft_hook` fields (e.g., `ifname`) after unlink/free, enabling arbitrary kernel memory read via heap grooming.
- I:HIntegrity impact, high
- The freed `nft_hook` kmalloc object can be reallocated and corrupted through the dangling RCU list pointers, providing a standard kernel UAF primitive exploitable for arbitrary write and control-flow hijacking.
- A:HAvailability impact, high
- The race reliably causes kernel list corruption and use-after-free, leading to oops/panic during hook dumps, flowtable lookups, or netns cleanup; UAF in this path has inherent high availability impact even when not fully weaponized.