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Fencer Vulns
high 7.5

CVE-2024-40957 json

seg6: fix parameter passing when calling NF_HOOK() in End.DX4 and End.DX6 behaviors

published 2024-07-12 2 y ago modified 2026-08-05 3 mo ago also EUVD-2024-38844

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.7%
EPSS 0.7% chance of exploitation in 30 days, percentile 54%
public exploits
0
none known

Summary

In the Linux kernel, the following vulnerability has been resolved:

seg6: fix parameter passing when calling NF_HOOK() in End.DX4 and End.DX6 behaviors

input_action_end_dx4() and input_action_end_dx6() are called NF_HOOK() for PREROUTING hook, in PREROUTING hook, we should passing a valid indev, and a NULL outdev to NF_HOOK(), otherwise may trigger a NULL pointer dereference, as below:

[74830.647293] BUG: kernel NULL pointer dereference, address: 0000000000000090 [74830.655633] #PF: supervisor read access in kernel mode [74830.657888] #PF: error_code(0x0000) - not-present page [74830.659500] PGD 0 P4D 0 [74830.660450] Oops: 0000 [#1] PREEMPT SMP PTI ... [74830.664953] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 [74830.666569] RIP: 0010:rpfilter_mt+0x44/0x15e [ipt_rpfilter] ... [74830.689725] Call Trace: [74830.690402] <IRQ> [74830.690953] ? show_trace_log_lvl+0x1c4/0x2df [74830.692020] ? show_trace_log_lvl+0x1c4/0x2df [74830.693095] ? ipt_do_table+0x286/0x710 [ip_tables] [74830.694275] ? __die_body.cold+0x8/0xd [74830.695205] ? page_fault_oops+0xac/0x140 [74830.696244] ? exc_page_fault+0x62/0x150 [74830.697225] ? asm_exc_page_fault+0x22/0x30 [74830.698344] ? rpfilter_mt+0x44/0x15e [ipt_rpfilter] [74830.699540] ipt_do_table+0x286/0x710 [ip_tables] [74830.700758] ? ip6_route_input+0x19d/0x240 [74830.701752] nf_hook_slow+0x3f/0xb0 [74830.702678] input_action_end_dx4+0x19b/0x1e0 [74830.703735] ? input_action_end_t+0xe0/0xe0 [74830.704734] seg6_local_input_core+0x2d/0x60 [74830.705782] lwtunnel_input+0x5b/0xb0 [74830.706690] __netif_receive_skb_one_core+0x63/0xa0 [74830.707825] process_backlog+0x99/0x140 [74830.709538] __napi_poll+0x2c/0x160 [74830.710673] net_rx_action+0x296/0x350 [74830.711860] __do_softirq+0xcb/0x2ac [74830.713049] do_softirq+0x63/0x90

input_action_end_dx4() passing a NULL indev to NF_HOOK(), and finally trigger a NULL dereference in rpfilter_mt()->rpfilter_is_loopback():

static bool rpfilter_is_loopback(const struct sk_buff *skb, const struct net_device *in) { // in is NULL return skb->pkt_type == PACKET_LOOPBACK || in->flags & IFF_LOOPBACK; }

Patch / fix

  • Linux Linux 5.15.162, 6.1.96, 6.6.36, 6.9.7, 6.10
  • linux Debian 12 6.1.99-1
  • linux Debian 14, Debian 13 6.9.7-1

debian advisories DEBIAN-CVE-2024-40957

  • linux Ubuntu 22.04 LTS 5.15.0-121.131
  • linux Ubuntu 24.04 LTS 6.8.0-44.44
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1069.75
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1015.16
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1068.76
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1014.16
  • linux-gke Ubuntu 22.04 LTS 5.15.0-1066.72
  • linux-gke Ubuntu 24.04 LTS 6.8.0-1010.13

ubuntu advisories UBUNTU-CVE-2024-40957

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel RHEL 9 5.14.0-427.33.1.el9_4
  • rv RHEL 9 5.14.0-427.33.1.el9_4
  • perf RHEL 9 5.14.0-427.33.1.el9_4
  • rtla RHEL 9 5.14.0-427.33.1.el9_4
  • bpftool RHEL 9 7.3.0-427.33.1.el9_4
  • libperf RHEL 9 5.14.0-427.33.1.el9_4
  • kernel-rt RHEL 9 5.14.0-427.33.1.el9_4
  • kernel-64k RHEL 9 5.14.0-427.33.1.el9_4

red hat advisories RHSA-2024:5928

  • kernel-rt Linux Micro 6.0 6.4.0-10.1
  • kernel-source-rt Linux Micro 6.0 6.4.0-10.1
  • kernel-livepatch-MICRO-6-0-RT_Update_2 Linux Micro 6.0 1-1.1
  • kernel-source Linux Micro 6.0 6.4.0-19.1
  • kernel-default Linux Micro 6.0 6.4.0-19.1
  • kernel-kvmsmall Linux Micro 6.0 6.4.0-19.1
  • kernel-default-base Linux Micro 6.0 6.4.0-17.1.1.51
  • kernel-livepatch-MICRO-6-0_Update_2 Linux Micro 6.0 1-1.1

suse advisories SUSE-SU-2025:20047-1SUSE-SU-2025:20044-1SUSE-SU-2024:3383-1SUSE-SU-2024:3195-1SUSE-SU-2024:3194-1

  • kernel AlmaLinux 9 5.14.0-427.33.1.el9_4
  • rv AlmaLinux 9 5.14.0-427.33.1.el9_4
  • perf AlmaLinux 9 5.14.0-427.33.1.el9_4
  • rtla AlmaLinux 9 5.14.0-427.33.1.el9_4
  • bpftool AlmaLinux 9 7.3.0-427.33.1.el9_4
  • libperf AlmaLinux 9 5.14.0-427.33.1.el9_4
  • kernel-rt AlmaLinux 9 5.14.0-427.33.1.el9_4
  • kernel-64k AlmaLinux 9 5.14.0-427.33.1.el9_4

almalinux advisories ALSA-2024:5928

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2024-40957 updated cvss 5.5

kernel: seg6: fix parameter passing when calling NF_HOOK() in End.DX4 and End.DX6 behaviors

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 9 kernel-rt, kernel-rt-kvm, kernel-rt-core, kernel-rt-modules, kernel-rt-debug-kvm, kernel-rt-debug-core, +12 more
    affected: workaround, no fix planned “Will not fix”
  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-427.33.1.el9_4, perf 5.14.0-427.33.1.el9_4, rtla 5.14.0-427.33.1.el9_4, kernel-devel-matched 5.14.0-427.33.1.el9_4, kernel-64k-devel-matched 5.14.0-427.33.1.el9_4, kernel-debug-devel-matched 5.14.0-427.33.1.el9_4, +6 more Red Hat Enterprise Linux BaseOS (v. 9) bpftool 7.3.0-427.33.1.el9_4, kernel 5.14.0-427.33.1.el9_4, kernel-64k 5.14.0-427.33.1.el9_4, kernel-core 5.14.0-427.33.1.el9_4, kernel-tools 5.14.0-427.33.1.el9_4, python3-perf 5.14.0-427.33.1.el9_4, +28 more Red Hat Enterprise Linux CRB (v. 9) libperf 5.14.0-427.33.1.el9_4, kernel-debuginfo-common-s390x 5.14.0-427.33.1.el9_4, kernel-debuginfo-common-x86_64 5.14.0-427.33.1.el9_4, kernel-debuginfo-common-aarch64 5.14.0-427.33.1.el9_4, kernel-debuginfo-common-ppc64le 5.14.0-427.33.1.el9_4 Red Hat Enterprise Linux NFV (v. 9) kernel-rt 5.14.0-427.33.1.el9_4, kernel-rt-kvm 5.14.0-427.33.1.el9_4, kernel-rt-core 5.14.0-427.33.1.el9_4, kernel-rt-modules 5.14.0-427.33.1.el9_4, kernel-rt-debug-kvm 5.14.0-427.33.1.el9_4, kernel-rt-debug-core 5.14.0-427.33.1.el9_4, +6 more Red Hat Enterprise Linux RT (v. 9) kernel-rt 5.14.0-427.33.1.el9_4, kernel-rt-core 5.14.0-427.33.1.el9_4, kernel-rt-modules 5.14.0-427.33.1.el9_4, kernel-rt-debug-core 5.14.0-427.33.1.el9_4, kernel-rt-modules-core 5.14.0-427.33.1.el9_4, kernel-rt-debug-modules 5.14.0-427.33.1.el9_4, +4 more
    fixed: vendor fix RHSA-2024:5928
  • Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2 y ago

Exploit prediction

0.73% chance of exploitation in the next 30 days, higher than 54% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Linux Linux

Classification

Weakness
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.