CVE-2024-56636

CVE-2024-56636 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.

Key facts

Description

In the Linux kernel, the following vulnerability has been resolved: geneve: do not assume mac header is set in geneve_xmit_skb() We should not assume mac header is set in output path. Use skb_eth_hdr() instead of eth_hdr() to fix the issue. sysbot reported the following : WARNING: CPU: 0 PID: 11635 at include/linux/skbuff.h:3052 skb_mac_header include/linux/skbuff.h:3052 [inline] WARNING: CPU: 0 PID: 11635 at include/linux/skbuff.h:3052 eth_hdr include/linux/if_ether.h:24 [inline] WARNING: CPU: 0 PID: 11635 at include/linux/skbuff.h:3052 geneve_xmit_skb drivers/net/geneve.c:898 [inline] WARNING: CPU: 0 PID: 11635 at include/linux/skbuff.h:3052 geneve_xmit+0x4c38/0x5730 drivers/net/geneve.c:1039 Modules linked in: CPU: 0 UID: 0 PID: 11635 Comm: syz.4.1423 Not tainted 6.12.0-syzkaller-10296-gaaf20f870da0 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 RIP: 0010:skb_mac_header include/linux/skbuff.h:3052 [inline] RIP: 0010:eth_hdr include/linux/if_ether.h:24 [inline] RIP: 0010:geneve_xmit_skb drivers/net/geneve.c:898 [inline] RIP: 0010:geneve_xmit+0x4c38/0x5730 drivers/net/geneve.c:1039 Code: 21 c6 02 e9 35 d4 ff ff e8 a5 48 4c fb 90 0f 0b 90 e9 fd f5 ff ff e8 97 48 4c fb 90 0f 0b 90 e9 d8 f5 ff ff e8 89 48 4c fb 90 <0f> 0b 90 e9 41 e4 ff ff e8 7b 48 4c fb 90 0f 0b 90 e9 cd e7 ff ff RSP: 0018:ffffc90003b2f870 EFLAGS: 00010283 RAX: 000000000000037a RBX: 000000000000ffff RCX: ffffc9000dc3d000 RDX: 0000000000080000 RSI: ffffffff86428417 RDI: 0000000000000003 RBP: ffffc90003b2f9f0 R08: 0000000000000003 R09: 000000000000ffff R10: 000000000000ffff R11: 0000000000000002 R12: ffff88806603c000 R13: 0000000000000000 R14: ffff8880685b2780 R15: 0000000000000e23 FS: 00007fdc2deed6c0(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b30a1dff8 CR3: 0000000056b8c000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> __netdev_start_xmit include/linux/netdevice.h:5002 [inline] netdev_start_xmit include/linux/netdevice.h:5011 [inline] __dev_direct_xmit+0x58a/0x720 net/core/dev.c:4490 dev_direct_xmit include/linux/netdevice.h:3181 [inline] packet_xmit+0x1e4/0x360 net/packet/af_packet.c:285 packet_snd net/packet/af_packet.c:3146 [inline] packet_sendmsg+0x2700/0x5660 net/packet/af_packet.c:3178 sock_sendmsg_nosec net/socket.c:711 [inline] __sock_sendmsg net/socket.c:726 [inline] __sys_sendto+0x488/0x4f0 net/socket.c:2197 __do_sys_sendto net/socket.c:2204 [inline] __se_sys_sendto net/socket.c:2200 [inline] __x64_sys_sendto+0xe0/0x1c0 net/socket.c:2200 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Frequently asked questions

What is CVE-2024-56636?
In the Linux kernel, the following vulnerability has been resolved: geneve: do not assume mac header is set in geneve_xmit_skb() We should not assume mac header is set in output path. Use skb_eth_hdr() instead of eth_hdr() to fix the issue. sysbot reported the following : WARNING: CPU: 0 PID: 11635 at include/linux/skbuff.h:3052 skb_mac_header include/linux/skbuff.h:3052 [inline] WARNING: CPU: 0 PID: 11635 at include/linux/skbuff.h:3052 eth_hdr include/linux/if_ether.h:24 [inline] WARNING: CPU: 0 PID: 11635 at include/linux/skbuff.h:3052 geneve_xmit_skb drivers/net/geneve.c:898 [inline] WARNING: CPU: 0 PID: 11635 at include/linux/skbuff.h:3052 geneve_xmit+0x4c38/0x5730 drivers/net/geneve.c:1039 Modules linked in: CPU: 0 UID: 0 PID: 11635 Comm: syz.4.1423 Not tainted 6.12.0-syzkaller-10296-gaaf20f870da0 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 RIP: 0010:skb_mac_header include/linux/skbuff.h:3052 [inline] RIP: 0010:eth_hdr include/linux/if_ether.h:24 [inline] RIP: 0010:geneve_xmit_skb drivers/net/geneve.c:898 [inline] RIP: 0010:geneve_xmit+0x4c38/0x5730 drivers/net/geneve.c:1039 Code: 21 c6 02 e9 35 d4 ff ff e8 a5 48 4c fb 90 0f 0b 90 e9 fd f5 ff ff e8 97 48 4c fb 90 0f 0b 90 e9 d8 f5 ff ff e8 89 48 4c fb 90 <0f> 0b 90 e9 41 e4 ff ff e8 7b 48 4c fb 90 0f 0b 90 e9 cd e7 ff ff RSP: 0018:ffffc90003b2f870 EFLAGS: 00010283 RAX: 000000000000037a RBX: 000000000000ffff RCX: ffffc9000dc3d000 RDX: 0000000000080000 RSI: ffffffff86428417 RDI: 0000000000000003 RBP: ffffc90003b2f9f0 R08: 0000000000000003 R09: 000000000000ffff R10: 000000000000ffff R11: 0000000000000002 R12: ffff88806603c000 R13: 0000000000000000 R14: ffff8880685b2780 R15: 0000000000000e23 FS: 00007fdc2deed6c0(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b30a1dff8 CR3: 0000000056b8c000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> __netdev_start_xmit include/linux/netdevice.h:5002 [inline] netdev_start_xmit include/linux/netdevice.h:5011 [inline] __dev_direct_xmit+0x58a/0x720 net/core/dev.c:4490 dev_direct_xmit include/linux/netdevice.h:3181 [inline] packet_xmit+0x1e4/0x360 net/packet/af_packet.c:285 packet_snd net/packet/af_packet.c:3146 [inline] packet_sendmsg+0x2700/0x5660 net/packet/af_packet.c:3178 sock_sendmsg_nosec net/socket.c:711 [inline] __sock_sendmsg net/socket.c:726 [inline] __sys_sendto+0x488/0x4f0 net/socket.c:2197 __do_sys_sendto net/socket.c:2204 [inline] __se_sys_sendto net/socket.c:2200 [inline] __x64_sys_sendto+0xe0/0x1c0 net/socket.c:2200 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f
How severe is CVE-2024-56636?
CVE-2024-56636 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-2024-56636 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (18th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2024-56636?
CVE-2024-56636 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-2024-56636?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2024-56636 have an EU (EUVD) identifier?
Yes. CVE-2024-56636 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2024-53284.
When was CVE-2024-56636 published?
CVE-2024-56636 was published on 2024-12-27 and last updated on 2026-06-17.

References

Affected products (2)

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