Linux Kernel up to 6.19.11 netfilter null pointer dereference

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CTI Interest Score
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Summaryinfo

A vulnerability, which was classified as critical, was found in Linux Kernel up to 6.1.167/6.6.133/6.12.80/6.18.21/6.19.11. This affects an unknown function of the component netfilter. The manipulation results in null pointer dereference. This vulnerability is identified as CVE-2026-31424. There is not any exploit available. You should upgrade the affected component.

Detailsinfo

A vulnerability classified as critical has been found in Linux Kernel up to 6.1.167/6.6.133/6.12.80/6.18.21/6.19.11. Affected is some unknown functionality of the component netfilter. The manipulation with an unknown input leads to a null pointer dereference vulnerability. CWE is classifying the issue as CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. This is going to have an impact on availability. CVE summarizes:

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.

The advisory is shared for download at git.kernel.org. This vulnerability is traded as CVE-2026-31424 since 03/09/2026. The exploitability is told to be difficult. There are neither technical details nor an exploit publicly available.

The vulnerability scanner Nessus provides a plugin with the ID 313522 (Amazon Linux 2023 : bpftool, kernel, kernel-devel (ALAS2023-2026-1681)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.1.168, 6.6.134, 6.12.81, 6.18.22 or 6.19.12 eliminates this vulnerability. Applying the patch 1cd6313c8644bfebbd813a05da9daa21b09dd68c/f00ac65c90ea475719e08d629e2e26c8b4e6999b/e7e1b6bcb389c8708003d40613a59ff2496f6b1f/dc3e27dd7d76e21106b8f9bbdc31f5da74a89014/3e79374b03bf9a2f282f0eb1d0ac3776f7e0f28a/3d5d488f11776738deab9da336038add95d342d1 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (313522), EUVD (EUVD-2026-21948) and CERT Bund (WID-SEC-2026-1088). Once again VulDB remains the best source for vulnerability data.

Affected

  • Google Container-Optimized OS
  • Debian Linux
  • Amazon Linux 2
  • Red Hat Enterprise Linux
  • Ubuntu Linux
  • SUSE Linux
  • Oracle Linux
  • SUSE openSUSE
  • RESF Rocky Linux
  • Microsoft Azure Linux
  • Open Source Linux Kernel

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.1
VulDB Meta Temp Score: 5.0

VulDB Base Score: 4.8
VulDB Temp Score: 4.6
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 5.5
NVD Vector: 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Null pointer dereference
CWE: CWE-476 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 313522
Nessus Name: Amazon Linux 2023 : bpftool, kernel, kernel-devel (ALAS2023-2026-1681)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.1.168/6.6.134/6.12.81/6.18.22/6.19.12
Patch: 1cd6313c8644bfebbd813a05da9daa21b09dd68c/f00ac65c90ea475719e08d629e2e26c8b4e6999b/e7e1b6bcb389c8708003d40613a59ff2496f6b1f/dc3e27dd7d76e21106b8f9bbdc31f5da74a89014/3e79374b03bf9a2f282f0eb1d0ac3776f7e0f28a/3d5d488f11776738deab9da336038add95d342d1

Timelineinfo

03/09/2026 CVE reserved
04/13/2026 +34 days Advisory disclosed
04/13/2026 +0 days VulDB entry created
06/18/2026 +66 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-31424 (🔒)
GCVE (CVE): GCVE-0-2026-31424
GCVE (VulDB): GCVE-100-357156
EUVD: 🔒
CERT Bund: WID-SEC-2026-1088 - Linux Kernel: Mehrere Schwachstellen

Entryinfo

Created: 04/13/2026 16:06
Updated: 06/18/2026 15:53
Changes: 04/13/2026 16:06 (59), 04/13/2026 19:05 (1), 05/10/2026 03:08 (2), 05/21/2026 00:34 (12), 06/18/2026 15:53 (7)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

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