CVE-2024-42270

CVE-2024-42270 is a medium-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 5.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-476.

Key facts

Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: iptables: Fix null-ptr-deref in iptable_nat_table_init(). We had a report that iptables-restore sometimes triggered null-ptr-deref at boot time. [0] The problem is that iptable_nat_table_init() is exposed to user space before the kernel fully initialises netns. In the small race window, a user could call iptable_nat_table_init() that accesses net_generic(net, iptable_nat_net_id), which is available only after registering iptable_nat_net_ops. Let's call register_pernet_subsys() before xt_register_template(). [0]: bpfilter: Loaded bpfilter_umh pid 11702 Started bpfilter BUG: kernel NULL pointer dereference, address: 0000000000000013 PF: supervisor write access in kernel mode PF: error_code(0x0002) - not-present page PGD 0 P4D 0 PREEMPT SMP NOPTI CPU: 2 PID: 11879 Comm: iptables-restor Not tainted 6.1.92-99.174.amzn2023.x86_64 #1 Hardware name: Amazon EC2 c6i.4xlarge/, BIOS 1.0 10/16/2017 RIP: 0010:iptable_nat_table_init (net/ipv4/netfilter/iptable_nat.c:87 net/ipv4/netfilter/iptable_nat.c:121) iptable_nat Code: 10 4c 89 f6 48 89 ef e8 0b 19 bb ff 41 89 c4 85 c0 75 38 41 83 c7 01 49 83 c6 28 41 83 ff 04 75 dc 48 8b 44 24 08 48 8b 0c 24 <48> 89 08 4c 89 ef e8 a2 3b a2 cf 48 83 c4 10 44 89 e0 5b 5d 41 5c RSP: 0018:ffffbef902843cd0 EFLAGS: 00010246 RAX: 0000000000000013 RBX: ffff9f4b052caa20 RCX: ffff9f4b20988d80 RDX: 0000000000000000 RSI: 0000000000000064 RDI: ffffffffc04201c0 RBP: ffff9f4b29394000 R08: ffff9f4b07f77258 R09: ffff9f4b07f77240 R10: 0000000000000000 R11: ffff9f4b09635388 R12: 0000000000000000 R13: ffff9f4b1a3c6c00 R14: ffff9f4b20988e20 R15: 0000000000000004 FS: 00007f6284340000(0000) GS:ffff9f51fe280000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000013 CR3: 00000001d10a6005 CR4: 00000000007706e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: <TASK> ? show_trace_log_lvl (arch/x86/kernel/dumpstack.c:259) ? show_trace_log_lvl (arch/x86/kernel/dumpstack.c:259) ? xt_find_table_lock (net/netfilter/x_tables.c:1259) ? __die_body.cold (arch/x86/kernel/dumpstack.c:478 arch/x86/kernel/dumpstack.c:420) ? page_fault_oops (arch/x86/mm/fault.c:727) ? exc_page_fault (./arch/x86/include/asm/irqflags.h:40 ./arch/x86/include/asm/irqflags.h:75 arch/x86/mm/fault.c:1470 arch/x86/mm/fault.c:1518) ? asm_exc_page_fault (./arch/x86/include/asm/idtentry.h:570) ? iptable_nat_table_init (net/ipv4/netfilter/iptable_nat.c:87 net/ipv4/netfilter/iptable_nat.c:121) iptable_nat xt_find_table_lock (net/netfilter/x_tables.c:1259) xt_request_find_table_lock (net/netfilter/x_tables.c:1287) get_info (net/ipv4/netfilter/ip_tables.c:965) ? security_capable (security/security.c:809 (discriminator 13)) ? ns_capable (kernel/capability.c:376 kernel/capability.c:397) ? do_ipt_get_ctl (net/ipv4/netfilter/ip_tables.c:1656) ? bpfilter_send_req (net/bpfilter/bpfilter_kern.c:52) bpfilter nf_getsockopt (net/netfilter/nf_sockopt.c:116) ip_getsockopt (net/ipv4/ip_sockglue.c:1827) __sys_getsockopt (net/socket.c:2327) __x64_sys_getsockopt (net/socket.c:2342 net/socket.c:2339 net/socket.c:2339) do_syscall_64 (arch/x86/entry/common.c:51 arch/x86/entry/common.c:81) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121) RIP: 0033:0x7f62844685ee Code: 48 8b 0d 45 28 0f 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 49 89 ca b8 37 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 0a c3 66 0f 1f 84 00 00 00 00 00 48 8b 15 09 RSP: 002b:00007ffd1f83d638 EFLAGS: 00000246 ORIG_RAX: 0000000000000037 RAX: ffffffffffffffda RBX: 00007ffd1f83d680 RCX: 00007f62844685ee RDX: 0000000000000040 RSI: 0000000000000000 RDI: 0000000000000004 RBP: 0000000000000004 R08: 00007ffd1f83d670 R09: 0000558798ffa2a0 R10: 00007ffd1f83d680 R11: 0000000000000246 R12: 00007ffd1f83e3b2 R13: 00007f6284 ---truncated---

Frequently asked questions

What is CVE-2024-42270?
In the Linux kernel, the following vulnerability has been resolved: netfilter: iptables: Fix null-ptr-deref in iptable_nat_table_init(). We had a report that iptables-restore sometimes triggered null-ptr-deref at boot time. [0] The problem is that iptable_nat_table_init() is exposed to user space before the kernel fully initialises netns. In the small race window, a user could call iptable_nat_table_init() that accesses net_generic(net, iptable_nat_net_id), which is available only after registering iptable_nat_net_ops. Let's call register_pernet_subsys() before xt_register_template(). [0]: bpfilter: Loaded bpfilter_umh pid 11702 Started bpfilter BUG: kernel NULL pointer dereference, address: 0000000000000013 PF: supervisor write access in kernel mode PF: error_code(0x0002) - not-present page PGD 0 P4D 0 PREEMPT SMP NOPTI CPU: 2 PID: 11879 Comm: iptables-restor Not tainted 6.1.92-99.174.amzn2023.x86_64 #1 Hardware name: Amazon EC2 c6i.4xlarge/, BIOS 1.0 10/16/2017 RIP: 0010:iptable_nat_table_init (net/ipv4/netfilter/iptable_nat.c:87 net/ipv4/netfilter/iptable_nat.c:121) iptable_nat Code: 10 4c 89 f6 48 89 ef e8 0b 19 bb ff 41 89 c4 85 c0 75 38 41 83 c7 01 49 83 c6 28 41 83 ff 04 75 dc 48 8b 44 24 08 48 8b 0c 24 <48> 89 08 4c 89 ef e8 a2 3b a2 cf 48 83 c4 10 44 89 e0 5b 5d 41 5c RSP: 0018:ffffbef902843cd0 EFLAGS: 00010246 RAX: 0000000000000013 RBX: ffff9f4b052caa20 RCX: ffff9f4b20988d80 RDX: 0000000000000000 RSI: 0000000000000064 RDI: ffffffffc04201c0 RBP: ffff9f4b29394000 R08: ffff9f4b07f77258 R09: ffff9f4b07f77240 R10: 0000000000000000 R11: ffff9f4b09635388 R12: 0000000000000000 R13: ffff9f4b1a3c6c00 R14: ffff9f4b20988e20 R15: 0000000000000004 FS: 00007f6284340000(0000) GS:ffff9f51fe280000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000013 CR3: 00000001d10a6005 CR4: 00000000007706e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: <TASK> ? show_trace_log_lvl (arch/x86/kernel/dumpstack.c:259) ? show_trace_log_lvl (arch/x86/kernel/dumpstack.c:259) ? xt_find_table_lock (net/netfilter/x_tables.c:1259) ? __die_body.cold (arch/x86/kernel/dumpstack.c:478 arch/x86/kernel/dumpstack.c:420) ? page_fault_oops (arch/x86/mm/fault.c:727) ? exc_page_fault (./arch/x86/include/asm/irqflags.h:40 ./arch/x86/include/asm/irqflags.h:75 arch/x86/mm/fault.c:1470 arch/x86/mm/fault.c:1518) ? asm_exc_page_fault (./arch/x86/include/asm/idtentry.h:570) ? iptable_nat_table_init (net/ipv4/netfilter/iptable_nat.c:87 net/ipv4/netfilter/iptable_nat.c:121) iptable_nat xt_find_table_lock (net/netfilter/x_tables.c:1259) xt_request_find_table_lock (net/netfilter/x_tables.c:1287) get_info (net/ipv4/netfilter/ip_tables.c:965) ? security_capable (security/security.c:809 (discriminator 13)) ? ns_capable (kernel/capability.c:376 kernel/capability.c:397) ? do_ipt_get_ctl (net/ipv4/netfilter/ip_tables.c:1656) ? bpfilter_send_req (net/bpfilter/bpfilter_kern.c:52) bpfilter nf_getsockopt (net/netfilter/nf_sockopt.c:116) ip_getsockopt (net/ipv4/ip_sockglue.c:1827) __sys_getsockopt (net/socket.c:2327) __x64_sys_getsockopt (net/socket.c:2342 net/socket.c:2339 net/socket.c:2339) do_syscall_64 (arch/x86/entry/common.c:51 arch/x86/entry/common.c:81) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121) RIP: 0033:0x7f62844685ee Code: 48 8b 0d 45 28 0f 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 49 89 ca b8 37 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 0a c3 66 0f 1f 84 00 00 00 00 00 48 8b 15 09 RSP: 002b:00007ffd1f83d638 EFLAGS: 00000246 ORIG_RAX: 0000000000000037 RAX: ffffffffffffffda RBX: 00007ffd1f83d680 RCX: 00007f62844685ee RDX: 0000000000000040 RSI: 0000000000000000 RDI: 0000000000000004 RBP: 0000000000000004 R08: 00007ffd1f83d670 R09: 0000558798ffa2a0 R10: 00007ffd1f83d680 R11: 0000000000000246 R12: 00007ffd1f83e3b2 R13: 00007f6284 ---truncated---
How severe is CVE-2024-42270?
CVE-2024-42270 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2024-42270 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (13th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2024-42270?
CVE-2024-42270 primarily affects Linux Linux Kernel. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2024-42270?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2024-42270 have an EU (EUVD) identifier?
Yes. CVE-2024-42270 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2024-39493.
When was CVE-2024-42270 published?
CVE-2024-42270 was published on 2024-08-17 and last updated on 2026-06-17.

References

Affected products (2)

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