CVE-2024-40957

MEDIUM
Published Jul 12, 2024 Modified Nov 3, 2025 CWE-476

Description

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; }

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CVSS v3.1 Score

5.5
MEDIUM
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Weakness Type (CWE)

CWE-476 CWE-476

Affected Products

Vendor Product
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel

References

Frequently Asked Questions

What is CVE-2024-40957? +
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; } It has a CVSS v3.1 base score of 5.5 (MEDIUM).
How severe is CVE-2024-40957? +
CVE-2024-40957 has a CVSS v3.1 score of 5.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.
What products are affected by CVE-2024-40957? +
CVE-2024-40957 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.
How do I check if I'm vulnerable to CVE-2024-40957? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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