{"cve":"CVE-2024-26636","nvd":{"published":"2024-03-18T11:15:10.363","modified":"2026-06-17T07:17:57.073","status":"Analyzed","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nllc: make llc_ui_sendmsg() more robust against bonding changes\n\nsyzbot was able to trick llc_ui_sendmsg(), allocating an skb with no\nheadroom, but subsequently trying to push 14 bytes of Ethernet header [1]\n\nLike some others, llc_ui_sendmsg() releases the socket lock before\ncalling sock_alloc_send_skb().\nThen it acquires it again, but does not redo all the sanity checks\nthat were performed.\n\nThis fix:\n\n- Uses LL_RESERVED_SPACE() to reserve space.\n- Check all conditions again after socket lock is held again.\n- Do not account Ethernet header for mtu limitation.\n\n[1]\n\nskbuff: skb_under_panic: text:ffff800088baa334 len:1514 put:14 head:ffff0000c9c37000 data:ffff0000c9c36ff2 tail:0x5dc end:0x6c0 dev:bond0\n\n kernel BUG at net/core/skbuff.c:193 !\nInternal error: Oops - BUG: 00000000f2000800 [#1] PREEMPT SMP\nModules linked in:\nCPU: 0 PID: 6875 Comm: syz-executor.0 Not tainted 6.7.0-rc8-syzkaller-00101-g0802e17d9aca-dirty #0\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023\npstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)\n pc : skb_panic net/core/skbuff.c:189 [inline]\n pc : skb_under_panic+0x13c/0x140 net/core/skbuff.c:203\n lr : skb_panic net/core/skbuff.c:189 [inline]\n lr : skb_under_panic+0x13c/0x140 net/core/skbuff.c:203\nsp : ffff800096f97000\nx29: ffff800096f97010 x28: ffff80008cc8d668 x27: dfff800000000000\nx26: ffff0000cb970c90 x25: 00000000000005dc x24: ffff0000c9c36ff2\nx23: ffff0000c9c37000 x22: 00000000000005ea x21: 00000000000006c0\nx20: 000000000000000e x19: ffff800088baa334 x18: 1fffe000368261ce\nx17: ffff80008e4ed000 x16: ffff80008a8310f8 x15: 0000000000000001\nx14: 1ffff00012df2d58 x13: 0000000000000000 x12: 0000000000000000\nx11: 0000000000000001 x10: 0000000000ff0100 x9 : e28a51f1087e8400\nx8 : e28a51f1087e8400 x7 : ffff80008028f8d0 x6 : 0000000000000000\nx5 : 0000000000000001 x4 : 0000000000000001 x3 : ffff800082b78714\nx2 : 0000000000000001 x1 : 0000000100000000 x0 : 0000000000000089\nCall trace:\n  skb_panic net/core/skbuff.c:189 [inline]\n  skb_under_panic+0x13c/0x140 net/core/skbuff.c:203\n  skb_push+0xf0/0x108 net/core/skbuff.c:2451\n  eth_header+0x44/0x1f8 net/ethernet/eth.c:83\n  dev_hard_header include/linux/netdevice.h:3188 [inline]\n  llc_mac_hdr_init+0x110/0x17c net/llc/llc_output.c:33\n  llc_sap_action_send_xid_c+0x170/0x344 net/llc/llc_s_ac.c:85\n  llc_exec_sap_trans_actions net/llc/llc_sap.c:153 [inline]\n  llc_sap_next_state net/llc/llc_sap.c:182 [inline]\n  llc_sap_state_process+0x1ec/0x774 net/llc/llc_sap.c:209\n  llc_build_and_send_xid_pkt+0x12c/0x1c0 net/llc/llc_sap.c:270\n  llc_ui_sendmsg+0x7bc/0xb1c net/llc/af_llc.c:997\n  sock_sendmsg_nosec net/socket.c:730 [inline]\n  __sock_sendmsg net/socket.c:745 [inline]\n  sock_sendmsg+0x194/0x274 net/socket.c:767\n  splice_to_socket+0x7cc/0xd58 fs/splice.c:881\n  do_splice_from fs/splice.c:933 [inline]\n  direct_splice_actor+0xe4/0x1c0 fs/splice.c:1142\n  splice_direct_to_actor+0x2a0/0x7e4 fs/splice.c:1088\n  do_splice_direct+0x20c/0x348 fs/splice.c:1194\n  do_sendfile+0x4bc/0xc70 fs/read_write.c:1254\n  __do_sys_sendfile64 fs/read_write.c:1322 [inline]\n  __se_sys_sendfile64 fs/read_write.c:1308 [inline]\n  __arm64_sys_sendfile64+0x160/0x3b4 fs/read_write.c:1308\n  __invoke_syscall arch/arm64/kernel/syscall.c:37 [inline]\n  invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:51\n  el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:136\n  do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:155\n  el0_svc+0x54/0x158 arch/arm64/kernel/entry-common.c:678\n  el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:696\n  el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:595\nCode: aa1803e6 aa1903e7 a90023f5 94792f6a (d4210000)","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","score":5.5},"cwes":[],"references":["https://git.kernel.org/stable/c/04f2a74b562f3a7498be0399309669f342793d8c","https://git.kernel.org/stable/c/6d53b813ff8b177f86f149c2f744442681f720e4","https://git.kernel.org/stable/c/84e9d10419f6f4f3f3cd8f9aaf44a48719aa4b1b","https://git.kernel.org/stable/c/b643d0defcbacd7fe548bc65c3e4e6f17dc5eb2d","https://git.kernel.org/stable/c/c22044270da68881074fda81a7d34812726cb249"],"products":["debian:debian_linux","linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T21:46:54.846886191+00:00"},"epss":{"cve":"CVE-2024-26636","score":0.0024,"percentile":0.15157,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}