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CVE-2026-74565
netfilter: nf_tables: make nft_object rhltable per table
Published 2026-08-15 (2 months ago) by the Linux kernel CNA. Subsystem include/net. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-74565 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 | fixedDLA-4841-1 · 2026-10-17 · text | 6.1.190-1 | Update the kernel and reboot. DLA-4841-1 shipped the fix on 2026-10-17, in 6.1.190-1. A running kernel keeps the old code until the machine restarts. |
| Debian 13trixie | fixedDSA-6466-1 · 2026-08-25 · text | 6.12.105-1 | Update the kernel and reboot. DSA-6466-1 shipped the fix on 2026-08-25, in 6.12.105-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.1.8-1 | Update the kernel and reboot. Fixed in 7.1.8-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.1.8-1 | Update the kernel and reboot. Fixed in 7.1.8-1. A running kernel keeps the old code until the machine restarts. |
| Debian 12bookworm · linux-6.12 | fixedDLA-4788-1 · 2026-09-19 · text | 6.12.107-1~deb12u1 | Update the kernel and reboot. DLA-4788-1 shipped the fix on 2026-09-19, in 6.12.107-1~deb12u1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
The nft_object rhltable is global, this allows for accessing objects that are being dismangled from lookup path by other existing netns. Given the nft_obj_destroy() releases the object inmediately, this might lead to use-after-free of these objects that are being released. Make the existing rhltable per table to address this issue to deal with with the nft_rcv_nl_event() path too. Update nft_obj_lookup() to take the table as non-const, otherwise, compiler complains when passing the objname_ht to rhltable_lookup().
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.
include/net/netfilter/nf_tables.h
net/netfilter/nf_tables_api.c
- What this is
- NETFILTERMAINTAINERS section matched on include/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, sid, bookworm · linux-6.12m
- 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
- 2026-08-15 (2 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 1.9% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- include/net
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 5.1 | 5.10.270 | 4b549d32d34e |
| 5.1 | 6.1.188 | 523c881661dd |
| 5.1 | 6.12.103 | 1948e4f85b85 |
| 5.1 | 6.18.44 | 63ba12b664a2 |
| 5.1 | 7.1.8 | 7d4789b58761 |
| 5.1 | 7.2 | f4f699790590 |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DLA-4841-1 | 2026-10-17 | bookworm 6.1.190-1 | tracker |
| DLA-4788-1 | 2026-09-19 | bookworm 6.12.107-1~deb12u1 | tracker |
| DSA-6466-1 | 2026-08-25 | trixie 6.12.105-1 | tracker |
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 UAF is triggered only through local NETLINK_NETFILTER nftables configuration syscalls (NFT_MSG_NEWOBJ/GETOBJ/DELOBJ and rule/objref setup) that call nft_obj_lookup(); per kernel CNA guidance, nf_tables/netlink is Local, not network-reachable packet processing.
- AC:LAttack complexity, low
- The attacker controls both sides of the race by running concurrent Netlink sockets—one closing to fire nft_rcv_nl_event()/__nft_release_table() object teardown and another issuing object lookups/commits—and can retry until the global rhltable collision-chain walk hits freed memory.
- PR:LPrivileges required, low
- All nf_tables Netlink handlers are gated by netlink_net_capable(skb, CAP_NET_ADMIN) in nfnetlink_rcv(); CAP_NET_ADMIN is obtainable by an unprivileged user inside a user+network namespace (unshare -Urn), not requiring init-namespace root.
- UI:NUser interaction, none
- No victim interaction is required; exploitation is fully attacker-driven through their own nftables Netlink operations and socket close events without another user mounting, opening files, or taking any action.
- S:UScope, unchanged
- Impact is kernel heap use-after-free and potential local privilege escalation within the same kernel security authority; this is standard in-kernel memory corruption, not a distinct VM-guest-to-host or sandbox-boundary escape.
- C:HConfidentiality impact, high
- nft_obj_lookup() holds rcu_read_lock and walks the global rhltable collision chain, dereferencing struct nft_object fields (key.table, ops, genmask) that nft_obj_destroy() may have already kfree'd, giving arbitrary kernel memory read potential from UAF.
- I:HIntegrity impact, high
- Immediate kfree after rhltable_remove without waiting for RCU readers enables classic slab UAF heap corruption that can be groomed into arbitrary kernel writes, control-flow hijacking, and local privilege escalation beyond a bounded or transient fault.
- A:HAvailability impact, high
- Concurrent destruction via nft_rcv_nl_event() and active nft_obj_lookup() reliably provokes KASAN-class slab use-after-free kernel oops/panic during rhlist traversal; UAF is inherently crash-prone even when not fully weaponized for code execution.