CVE-2026-31424
What it is
In the Linux kernel, the following vulnerability has been resolved: netfilter: x_tables: restrict xt_check_match/xt_check_target extensions for NFPROTO_ARP Weiming Shi says: xt_match and xt_target structs registered with NFPROTO_UNSPEC can be loaded by any protocol family through nft_compat. When such a match/target sets .hooks to restrict which hooks it may run on, the bitmask uses NF_INET_* constants. This is only correct for families whose hook layout matches NF_INET_*: IPv4, IPv6, INET, and bridge all share the same five hooks (PRE_ROUTING ... POST_ROUTING). ARP only has three hooks (IN=0, OUT=1, FORWARD=2) with different semantics. Because NF_ARP_OUT == 1 == NF_INET_LOCAL_IN, the .hooks validation silently passes for the wrong reasons, allowing matches to run on ARP chains where the hook assumptions (e.g. state->in being set on input hooks) do not hold. This leads to NULL pointer dereferences; xt_devgroup is one concrete example: Oops: general protection fault, probably for non-canonical address 0xdffffc0000000044: 0000 [#1] SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000220-0x0000000000000227] RIP: 0010:devgroup_mt+0xff/0x350 Call Trace: <TASK> nft_match_eval (net/netfilter/nft_compat.c:407) nft_do_chain (net/netfilter/nf_tables_core.c:285) nft_do_chain_arp (net/netfilter/nft_chain_filter.c:61) nf_hook_slow (net/netfilter/core.c:623) arp_xmit (net/ipv4/arp.c:666) </TASK> Kernel panic - not syncing: Fatal exception in interrupt Fix it by restricting arptables to NFPROTO_ARP extensions only. Note that arptables-legacy only supports: - arpt_CLASSIFY - arpt_mangle - arpt_MARK that provide explicit NFPROTO_ARP match/target declarations.
At a glance
- Exploitability
- Can be exploited locally on the machine with a low-privilege account. High risk of service disruption.
- Exploit odds
- 0.1% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 0.1% in the next 30 days (EPSS).
- Severity: 5.5 MEDIUM (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 0.1% · EPSS, next 30 days
- Weakness
- CWE-476 · NULL pointer dereference
- Record status
- Modified
Affected
- Linux Kernel < 5.10.253
- Linux Kernel < 5.15.203
- Linux Kernel < 6.1.168
- Linux Kernel < 6.6.134
- Linux Kernel < 6.12.81
- Linux Kernel < 6.18.22
- Linux Kernel < 6.19.12
- Linux Kernel 7.0
Attack profile CVSS 3.1 · 5.5
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Raw vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2026-31424.md and follow it. Check whether this project is affected by CVE-2026-31424. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- https://git.kernel.org/stable/c/1cd6313c8644bfebbd813a05da9daa21b09dd68c
- https://git.kernel.org/stable/c/3d5d488f11776738deab9da336038add95d342d1
- https://git.kernel.org/stable/c/3e79374b03bf9a2f282f0eb1d0ac3776f7e0f28a
- https://git.kernel.org/stable/c/80e3c75f71c3ea1e62fcb032382de13e00a68f8b
- https://git.kernel.org/stable/c/d9a0af9e43416aa50c0595e15fa01365a1c72c49
- https://git.kernel.org/stable/c/dc3e27dd7d76e21106b8f9bbdc31f5da74a89014
- https://git.kernel.org/stable/c/e7e1b6bcb389c8708003d40613a59ff2496f6b1f
- https://git.kernel.org/stable/c/f00ac65c90ea475719e08d629e2e26c8b4e6999b
References
- https://git.kernel.org/stable/c/1cd6313c8644bfebbd813a05da9daa21b09dd68c
- https://git.kernel.org/stable/c/3d5d488f11776738deab9da336038add95d342d1
- https://git.kernel.org/stable/c/3e79374b03bf9a2f282f0eb1d0ac3776f7e0f28a
- https://git.kernel.org/stable/c/80e3c75f71c3ea1e62fcb032382de13e00a68f8b
- https://git.kernel.org/stable/c/d9a0af9e43416aa50c0595e15fa01365a1c72c49
- https://git.kernel.org/stable/c/dc3e27dd7d76e21106b8f9bbdc31f5da74a89014
- https://git.kernel.org/stable/c/e7e1b6bcb389c8708003d40613a59ff2496f6b1f
- https://git.kernel.org/stable/c/f00ac65c90ea475719e08d629e2e26c8b4e6999b
- https://cert-portal.siemens.com/productcert/html/ssa-019113.html
- https://cert-portal.siemens.com/productcert/html/ssa-082556.html
- https://cert-portal.siemens.com/productcert/html/ssa-457936.html