medium 5.5

CVE-2024-56636 json

geneve: do not assume mac header is set in geneve_xmit_skb()

published 2024-12-27 last yr. modified 2026-11-05 6d ago also EUVD-2024-53284

cvss: 5.5; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 0.3%; EPSS 0.3% chance of exploitation in 30 days, percentile 19%
public exploits: 0; none known

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

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

Patch / fix

fixed in 1 distros 3 links 6

Linux Linux 5.10.231, 5.15.174, 6.1.120, 6.6.66, 6.12.5, 6.13

debian ubuntu suse

linux Debian 12 6.1.123-1
linux Debian 14, Debian 13 6.12.5-1

debian advisories DEBIAN-CVE-2024-56636

linux Ubuntu 22.04 LTS 5.15.0-135.146
linux Ubuntu 24.04 LTS 6.8.0-58.60
linux-aws Ubuntu 22.04 LTS 5.15.0-1080.87
linux-aws Ubuntu 24.04 LTS 6.8.0-1027.29
linux-gcp Ubuntu 22.04 LTS 5.15.0-1079.88
linux-gcp Ubuntu 24.04 LTS 6.8.0-1028.30
linux-gke Ubuntu 22.04 LTS 5.15.0-1077.83
linux-gke Ubuntu 24.04 LTS 6.8.0-1023.27

ubuntu advisories UBUNTU-CVE-2024-56636

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-rt Linux Micro 6.1, Linux Micro 6.0 6.4.0-25.1
kernel-source-rt Linux Micro 6.1, Linux Micro 6.0 6.4.0-25.1
kernel-livepatch-MICRO-6-0-RT_Update_5 Linux Micro 6.1, Linux Micro 6.0 1-1.1
kernel-source Linux Micro 6.1, Linux Micro 6.0 6.4.0-25.1
kernel-default Linux Micro 6.1, Linux Micro 6.0 6.4.0-25.1
kernel-kvmsmall Linux Micro 6.1, Linux Micro 6.0 6.4.0-25.1
kernel-default-base Linux Micro 6.1, Linux Micro 6.0 6.4.0-24.1.21.4
kernel-livepatch-MICRO-6-0_Update_5 Linux Micro 6.1, Linux Micro 6.0 1-1.2

suse advisories SUSE-SU-2025:20166-1 SUSE-SU-2025:20249-1 SUSE-SU-2025:20165-1 SUSE-SU-2025:20248-1 SUSE-SU-2025:0557-1 SUSE-SU-2025:0499-1

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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-2024-56636 updated 2026-11-05 cvss 4.7

kernel: geneve: do not assume mac header is set in geneve_xmit_skb()

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 Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more
affected: workaround, no fix planned “To mitigate this issue, prevent module geneve from being loaded. Please see https://access.redhat.com/solutions/41278 for how to blacklist a kernel module to prevent it from loading automatically.”
Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +82 more
affected: workaround, no fix available “To mitigate this issue, prevent module geneve from being loaded. Please see https://access.redhat.com/solutions/41278 for how to blacklist a kernel module to prevent it from loading automatically.”

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 ICSA-25-226-07 updated 2026-02-25 cvss 4.7

Siemens Third-Party Components in SINEC OS

Siemens RUGGEDCOM RST2428P (6GK6242-6PA00) < 3.2
affected: fixed in V3.2 support.industry.siemens.com
Siemens SCALANCE XC-300/XR-300/XC-400/XR-500WG/XR-500 family < 3.2
affected: fixed in V3.2
Siemens SCALANCE XCM-/XRM-/XCH-/XRH-300 family < 3.2
affected: fixed in V3.2 support.industry.siemens.com

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 6d ago (2026-11-05)

Exploit prediction

0.27% chance of exploitation in the next 30 days, higher than 19% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by	version	score	vector
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

Technology feeds

Linux kernel rss critical rss

References

Sources

CVE List CVE-2024-56636
NVD CVE-2024-56636

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