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CVE-2026-52988
netfilter: nf_tables: join hook list via splice_list_rcu() in commit phase
Published 2026-06-24 (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-2026-52988 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-6568-1 · 2026-10-16 · text | 6.12.113-1 | Update the kernel and reboot. DSA-6568-1 shipped the fix on 2026-10-16, in 6.12.113-1. A running kernel keeps the old code until the machine restarts. |
| 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
Publish new hooks in the list into the basechain/flowtable using splice_list_rcu() to ensure netlink dump list traversal via rcu is safe while concurrent ruleset update is going on.
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
- 2026-06-24 (4 months ago)source
- CVSS
- 7.1 high
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.13%, higher than 2.4% 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 |
|---|---|---|
| 5.8 | 5.10.271 | ed8d3bd8272e |
| 5.8 | 5.15.222 | 8fdd2204503a |
| 5.8 | 6.1.189 | 5593c640f9da |
| 5.8 | 6.6.158 | 00e370627f2e |
| 5.8 | 6.12.112 | 28ecfb3d1fe8 |
| 5.8 | 6.18.55 | a557816c6e38 |
| 5.8 | 7.0.10 | 1346be937963 |
| 5.8 | 7.1 | a6134e62dba2 |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DLA-4841-1 | 2026-10-17 | bookworm 6.1.190-1 | tracker |
| DSA-6568-1 | 2026-10-16 | trixie 6.12.113-1 | 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
- Reachability is through nfnetlink/nftables netlink operations (`NFT_MSG_NEWCHAIN`/`NEWFLOWTABLE` and concurrent `GETCHAIN`/`GETFLOWTABLE` dumps), which require local ability to send netlink messages.
- AC:LAttack complexity, low
- The bug is a race between an attacker-controlled ruleset update and an attacker-controlled concurrent RCU dump; both sides can be generated repeatedly from local processes.
- PR:LPrivileges required, low
- nfnetlink checks `CAP_NET_ADMIN` in the target network namespace, and nftables/netfilter administration is reachable from unprivileged users via user+network namespaces on affected configurations.
- UI:NUser interaction, none
- No victim interaction is required; the attacker triggers both the update and dump operations directly.
- S:UScope, unchanged
- The impact remains within the kernel/local host security authority and does not cross a VM, IOMMU, or separate security-scope boundary.
- C:HConfidentiality impact, high
- Unsafe non-RCU list publication can make an RCU netlink dump interpret a transaction list head or freed transaction memory as `struct nft_hook`, leading to out-of-bounds/use-after-free reads returned through netlink hook device-name serialization.
- I:NIntegrity impact, none
- The reachable affected dump path reads hook-list entries and serializes names; I did not find a defensible attacker-controlled write or control-flow primitive from this bug.
- A:HAvailability impact, high
- The malformed RCU traversal can dereference invalid/freed memory or loop over an inconsistent list, making kernel oops, panic, or soft lockup a plausible outcome.