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

icmp6: Fix null-ptr-deref of ip6_null_entry->rt6i_idev in icmp6_dev().

With some IPv6 Ext Hdr (RPL, SRv6, etc.), we can send a packet that
has the link-local address as src and dst IP and will be forwarded to
an external IP in the IPv6 Ext Hdr.

For example, the script below generates a packet whose src IP is the
link-local address and dst is updated to 11::.

# for f in $(find /proc/sys/net/ -name *seg6_enabled*); do echo 1 > $f; done
# python3
>>> from socket import *
>>> from scapy.all import *
>>>
>>> SRC_ADDR = DST_ADDR = "fe80::5054:ff:fe12:3456"
>>>
>>> pkt = IPv6(src=SRC_ADDR, dst=DST_ADDR)
>>> pkt /= IPv6ExtHdrSegmentRouting(type=4, addresses=["11::", "22::"], segleft=1)
>>>
>>> sk = socket(AF_INET6, SOCK_RAW, IPPROTO_RAW)
>>> sk.sendto(bytes(pkt), (DST_ADDR, 0))

For such a packet, we call ip6_route_input() to look up a route for the
next destination in these three functions depending on the header type.

* ipv6_rthdr_rcv()
* ipv6_rpl_srh_rcv()
* ipv6_srh_rcv()

If no route is found, ip6_null_entry is set to skb, and the following
dst_input(skb) calls ip6_pkt_drop().

Finally, in icmp6_dev(), we dereference skb_rt6_info(skb)->rt6i_idev->dev
as the input device is the loopback interface. Then, we have to check if
skb_rt6_info(skb)->rt6i_idev is NULL or not to avoid NULL pointer deref
for ip6_null_entry.

BUG: kernel NULL pointer dereference, address: 0000000000000000
PF: supervisor read access in kernel mode
PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: 0000 [#1] PREEMPT SMP PTI
CPU: 0 PID: 157 Comm: python3 Not tainted 6.4.0-11996-gb121d614371c #35
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014
RIP: 0010:icmp6_send (net/ipv6/icmp.c:436 net/ipv6/icmp.c:503)
Code: fe ff ff 48 c7 40 30 c0 86 5d 83 e8 c6 44 1c 00 e9 c8 fc ff ff 49 8b 46 58 48 83 e0 fe 0f 84 4a fb ff ff 48 8b 80 d0 00 00 00 <48> 8b 00 44 8b 88 e0 00 00 00 e9 34 fb ff ff 4d 85 ed 0f 85 69 01
RSP: 0018:ffffc90000003c70 EFLAGS: 00000286
RAX: 0000000000000000 RBX: 0000000000000001 RCX: 00000000000000e0
RDX: 0000000000000021 RSI: 0000000000000000 RDI: ffff888006d72a18
RBP: ffffc90000003d80 R08: 0000000000000000 R09: 0000000000000001
R10: ffffc90000003d98 R11: 0000000000000040 R12: ffff888006d72a10
R13: 0000000000000000 R14: ffff8880057fb800 R15: ffffffff835d86c0
FS: 00007f9dc72ee740(0000) GS:ffff88807dc00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 00000000057b2000 CR4: 00000000007506f0
PKRU: 55555554
Call Trace:
<IRQ>
ip6_pkt_drop (net/ipv6/route.c:4513)
ipv6_rthdr_rcv (net/ipv6/exthdrs.c:640 net/ipv6/exthdrs.c:686)
ip6_protocol_deliver_rcu (net/ipv6/ip6_input.c:437 (discriminator 5))
ip6_input_finish (./include/linux/rcupdate.h:781 net/ipv6/ip6_input.c:483)
__netif_receive_skb_one_core (net/core/dev.c:5455)
process_backlog (./include/linux/rcupdate.h:781 net/core/dev.c:5895)
__napi_poll (net/core/dev.c:6460)
net_rx_action (net/core/dev.c:6529 net/core/dev.c:6660)
__do_softirq (./arch/x86/include/asm/jump_label.h:27 ./include/linux/jump_label.h:207 ./include/trace/events/irq.h:142 kernel/softirq.c:554)
do_softirq (kernel/softirq.c:454 kernel/softirq.c:441)
</IRQ>
<TASK>
__local_bh_enable_ip (kernel/softirq.c:381)
__dev_queue_xmit (net/core/dev.c:4231)
ip6_finish_output2 (./include/net/neighbour.h:544 net/ipv6/ip6_output.c:135)
rawv6_sendmsg (./include/net/dst.h:458 ./include/linux/netfilter.h:303 net/ipv6/raw.c:656 net/ipv6/raw.c:914)
sock_sendmsg (net/socket.c:725 net/socket.c:748)
__sys_sendto (net/socket.c:2134)
__x64_sys_sendto (net/socket.c:2146 net/socket.c:2142 net/socket.c:2142)
do_syscall_64 (arch/x86/entry/common.c:50 arch/x86/entry/common.c:80)
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:120)
RIP: 0033:0x7f9dc751baea
Code: d8 64 89 02 48 c7 c0 ff f
---truncated---
Published: 2025-09-17
Score: 5.5 Medium
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

Analysis and contextual insights are available on OpenCVE Cloud.

Remediation

No vendor fix or workaround currently provided.

Additional remediation guidance may be available on OpenCVE Cloud.

Tracking

Sign in to view the affected projects.

Advisories
Source ID Title
EUVD EUVD EUVD-2023-59983 In the Linux kernel, the following vulnerability has been resolved: icmp6: Fix null-ptr-deref of ip6_null_entry->rt6i_idev in icmp6_dev(). With some IPv6 Ext Hdr (RPL, SRv6, etc.), we can send a packet that has the link-local address as src and dst IP and will be forwarded to an external IP in the IPv6 Ext Hdr. For example, the script below generates a packet whose src IP is the link-local address and dst is updated to 11::. # for f in $(find /proc/sys/net/ -name *seg6_enabled*); do echo 1 > $f; done # python3 >>> from socket import * >>> from scapy.all import * >>> >>> SRC_ADDR = DST_ADDR = "fe80::5054:ff:fe12:3456" >>> >>> pkt = IPv6(src=SRC_ADDR, dst=DST_ADDR) >>> pkt /= IPv6ExtHdrSegmentRouting(type=4, addresses=["11::", "22::"], segleft=1) >>> >>> sk = socket(AF_INET6, SOCK_RAW, IPPROTO_RAW) >>> sk.sendto(bytes(pkt), (DST_ADDR, 0)) For such a packet, we call ip6_route_input() to look up a route for the next destination in these three functions depending on the header type. * ipv6_rthdr_rcv() * ipv6_rpl_srh_rcv() * ipv6_srh_rcv() If no route is found, ip6_null_entry is set to skb, and the following dst_input(skb) calls ip6_pkt_drop(). Finally, in icmp6_dev(), we dereference skb_rt6_info(skb)->rt6i_idev->dev as the input device is the loopback interface. Then, we have to check if skb_rt6_info(skb)->rt6i_idev is NULL or not to avoid NULL pointer deref for ip6_null_entry. BUG: kernel NULL pointer dereference, address: 0000000000000000 PF: supervisor read access in kernel mode PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] PREEMPT SMP PTI CPU: 0 PID: 157 Comm: python3 Not tainted 6.4.0-11996-gb121d614371c #35 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014 RIP: 0010:icmp6_send (net/ipv6/icmp.c:436 net/ipv6/icmp.c:503) Code: fe ff ff 48 c7 40 30 c0 86 5d 83 e8 c6 44 1c 00 e9 c8 fc ff ff 49 8b 46 58 48 83 e0 fe 0f 84 4a fb ff ff 48 8b 80 d0 00 00 00 <48> 8b 00 44 8b 88 e0 00 00 00 e9 34 fb ff ff 4d 85 ed 0f 85 69 01 RSP: 0018:ffffc90000003c70 EFLAGS: 00000286 RAX: 0000000000000000 RBX: 0000000000000001 RCX: 00000000000000e0 RDX: 0000000000000021 RSI: 0000000000000000 RDI: ffff888006d72a18 RBP: ffffc90000003d80 R08: 0000000000000000 R09: 0000000000000001 R10: ffffc90000003d98 R11: 0000000000000040 R12: ffff888006d72a10 R13: 0000000000000000 R14: ffff8880057fb800 R15: ffffffff835d86c0 FS: 00007f9dc72ee740(0000) GS:ffff88807dc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 00000000057b2000 CR4: 00000000007506f0 PKRU: 55555554 Call Trace: <IRQ> ip6_pkt_drop (net/ipv6/route.c:4513) ipv6_rthdr_rcv (net/ipv6/exthdrs.c:640 net/ipv6/exthdrs.c:686) ip6_protocol_deliver_rcu (net/ipv6/ip6_input.c:437 (discriminator 5)) ip6_input_finish (./include/linux/rcupdate.h:781 net/ipv6/ip6_input.c:483) __netif_receive_skb_one_core (net/core/dev.c:5455) process_backlog (./include/linux/rcupdate.h:781 net/core/dev.c:5895) __napi_poll (net/core/dev.c:6460) net_rx_action (net/core/dev.c:6529 net/core/dev.c:6660) __do_softirq (./arch/x86/include/asm/jump_label.h:27 ./include/linux/jump_label.h:207 ./include/trace/events/irq.h:142 kernel/softirq.c:554) do_softirq (kernel/softirq.c:454 kernel/softirq.c:441) </IRQ> <TASK> __local_bh_enable_ip (kernel/softirq.c:381) __dev_queue_xmit (net/core/dev.c:4231) ip6_finish_output2 (./include/net/neighbour.h:544 net/ipv6/ip6_output.c:135) rawv6_sendmsg (./include/net/dst.h:458 ./include/linux/netfilter.h:303 net/ipv6/raw.c:656 net/ipv6/raw.c:914) sock_sendmsg (net/socket.c:725 net/socket.c:748) __sys_sendto (net/socket.c:2134) __x64_sys_sendto (net/socket.c:2146 net/socket.c:2142 net/socket.c:2142) do_syscall_64 (arch/x86/entry/common.c:50 arch/x86/entry/common.c:80) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:120) RIP: 0033:0x7f9dc751baea Code: d8 64 89 02 48 c7 c0 ff f ---truncated---
History

Wed, 14 Jan 2026 19:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Thu, 11 Dec 2025 13:00:00 +0000

Type Values Removed Values Added
Weaknesses CWE-476
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.5:rc1:*:*:*:*:*:*
Metrics cvssV3_1

{'score': 7.0, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'}

 cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

Thu, 18 Sep 2025 12:00:00 +0000

Type Values Removed Values Added
First Time appeared Linux
Linux linux Kernel
Vendors & Products Linux
Linux linux Kernel

Thu, 18 Sep 2025 00:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

 cvssV3_1

{'score': 7.0, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'}

threat_severity

Moderate

Wed, 17 Sep 2025 15:00:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: icmp6: Fix null-ptr-deref of ip6_null_entry->rt6i_idev in icmp6_dev(). With some IPv6 Ext Hdr (RPL, SRv6, etc.), we can send a packet that has the link-local address as src and dst IP and will be forwarded to an external IP in the IPv6 Ext Hdr. For example, the script below generates a packet whose src IP is the link-local address and dst is updated to 11::. # for f in $(find /proc/sys/net/ -name *seg6_enabled*); do echo 1 > $f; done # python3 >>> from socket import * >>> from scapy.all import * >>> >>> SRC_ADDR = DST_ADDR = "fe80::5054:ff:fe12:3456" >>> >>> pkt = IPv6(src=SRC_ADDR, dst=DST_ADDR) >>> pkt /= IPv6ExtHdrSegmentRouting(type=4, addresses=["11::", "22::"], segleft=1) >>> >>> sk = socket(AF_INET6, SOCK_RAW, IPPROTO_RAW) >>> sk.sendto(bytes(pkt), (DST_ADDR, 0)) For such a packet, we call ip6_route_input() to look up a route for the next destination in these three functions depending on the header type. * ipv6_rthdr_rcv() * ipv6_rpl_srh_rcv() * ipv6_srh_rcv() If no route is found, ip6_null_entry is set to skb, and the following dst_input(skb) calls ip6_pkt_drop(). Finally, in icmp6_dev(), we dereference skb_rt6_info(skb)->rt6i_idev->dev as the input device is the loopback interface. Then, we have to check if skb_rt6_info(skb)->rt6i_idev is NULL or not to avoid NULL pointer deref for ip6_null_entry. BUG: kernel NULL pointer dereference, address: 0000000000000000 PF: supervisor read access in kernel mode PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] PREEMPT SMP PTI CPU: 0 PID: 157 Comm: python3 Not tainted 6.4.0-11996-gb121d614371c #35 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014 RIP: 0010:icmp6_send (net/ipv6/icmp.c:436 net/ipv6/icmp.c:503) Code: fe ff ff 48 c7 40 30 c0 86 5d 83 e8 c6 44 1c 00 e9 c8 fc ff ff 49 8b 46 58 48 83 e0 fe 0f 84 4a fb ff ff 48 8b 80 d0 00 00 00 <48> 8b 00 44 8b 88 e0 00 00 00 e9 34 fb ff ff 4d 85 ed 0f 85 69 01 RSP: 0018:ffffc90000003c70 EFLAGS: 00000286 RAX: 0000000000000000 RBX: 0000000000000001 RCX: 00000000000000e0 RDX: 0000000000000021 RSI: 0000000000000000 RDI: ffff888006d72a18 RBP: ffffc90000003d80 R08: 0000000000000000 R09: 0000000000000001 R10: ffffc90000003d98 R11: 0000000000000040 R12: ffff888006d72a10 R13: 0000000000000000 R14: ffff8880057fb800 R15: ffffffff835d86c0 FS: 00007f9dc72ee740(0000) GS:ffff88807dc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 00000000057b2000 CR4: 00000000007506f0 PKRU: 55555554 Call Trace: <IRQ> ip6_pkt_drop (net/ipv6/route.c:4513) ipv6_rthdr_rcv (net/ipv6/exthdrs.c:640 net/ipv6/exthdrs.c:686) ip6_protocol_deliver_rcu (net/ipv6/ip6_input.c:437 (discriminator 5)) ip6_input_finish (./include/linux/rcupdate.h:781 net/ipv6/ip6_input.c:483) __netif_receive_skb_one_core (net/core/dev.c:5455) process_backlog (./include/linux/rcupdate.h:781 net/core/dev.c:5895) __napi_poll (net/core/dev.c:6460) net_rx_action (net/core/dev.c:6529 net/core/dev.c:6660) __do_softirq (./arch/x86/include/asm/jump_label.h:27 ./include/linux/jump_label.h:207 ./include/trace/events/irq.h:142 kernel/softirq.c:554) do_softirq (kernel/softirq.c:454 kernel/softirq.c:441) </IRQ> <TASK> __local_bh_enable_ip (kernel/softirq.c:381) __dev_queue_xmit (net/core/dev.c:4231) ip6_finish_output2 (./include/net/neighbour.h:544 net/ipv6/ip6_output.c:135) rawv6_sendmsg (./include/net/dst.h:458 ./include/linux/netfilter.h:303 net/ipv6/raw.c:656 net/ipv6/raw.c:914) sock_sendmsg (net/socket.c:725 net/socket.c:748) __sys_sendto (net/socket.c:2134) __x64_sys_sendto (net/socket.c:2146 net/socket.c:2142 net/socket.c:2142) do_syscall_64 (arch/x86/entry/common.c:50 arch/x86/entry/common.c:80) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:120) RIP: 0033:0x7f9dc751baea Code: d8 64 89 02 48 c7 c0 ff f ---truncated---
Title icmp6: Fix null-ptr-deref of ip6_null_entry->rt6i_idev in icmp6_dev().
References

Subscriptions

Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-05-11T19:43:06.840Z

Reserved: 2025-09-16T16:08:59.566Z

Link: CVE-2023-53343

cve-icon Vulnrichment

Updated: 2026-01-14T18:39:14.415Z

cve-icon NVD

Status : Modified

Published: 2025-09-17T15:15:38.100

Modified: 2026-01-14T19:16:29.743

Link: CVE-2023-53343

cve-icon Redhat

Severity : Moderate

Publid Date: 2025-09-17T00:00:00Z

Links: CVE-2023-53343 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2025-09-18T11:59:07Z

Weaknesses