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Linux KernelOperating system · Linux

CVE-2024-56636

MEDIUM · 5.5 CVSS v3.1 Published 2024-12-27
Fix available
A fix is available. Upgrade to 5.10.231 / 5.15.174 or later.
See remediation →
57/100
Remediation priority · Elevated
Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis

A detailed technical summary for this CVE is being prepared.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Linux KernelOperating system
Affected:>= 5.0, < 5.10.231>= 5.11, < 5.15.174>= 5.16, < 6.1.120>= 6.2, < 6.6.66>= 6.7, < 6.12.5= 6.13

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

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

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 5.10.231 / 5.15.174 / 6.1.120 or later
Fixed in 5.10.2315.15.1746.1.120
Vendor patch git.kernel.org →
Recommended fix High confidence

Kernel 5.10.231+, 5.15.174+, 6.1.120+, or 6.6.66+ depending on current branch

  1. Upgrade the Linux kernel to version 5.10.231 or later if running 5.10.x series
  2. Upgrade to 5.15.174 or later if running 5.11-5.15.x series
  3. Upgrade to 6.1.120 or later if running 5.16-6.1.x series
  4. Upgrade to 6.6.66 or later if running 6.2-6.6.x series
  5. After upgrading, verify the fix by checking that geneve_xmit_skb() uses skb_eth_hdr() instead of eth_hdr()
Caveat Standard kernel upgrade risks apply - ensure compatibility with userspace tools and drivers before deploying in production

Generated from the published advisory — verify against the referenced sources before acting.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2024-56636 in production — separate from our analysis above.

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