GHSA-5WW3-M3HH-C9FG
Vulnerability from github – Published: 2026-01-25 15:30 – Updated: 2026-07-14 15:31In the Linux kernel, the following vulnerability has been resolved:
ipv4: ip_gre: make ipgre_header() robust
Analog to commit db5b4e39c4e6 ("ip6_gre: make ip6gre_header() robust")
Over the years, syzbot found many ways to crash the kernel in ipgre_header() [1].
This involves team or bonding drivers ability to dynamically change their dev->needed_headroom and/or dev->hard_header_len
In this particular crash mld_newpack() allocated an skb with a too small reserve/headroom, and by the time mld_sendpack() was called, syzbot managed to attach an ipgre device.
[1] skbuff: skb_under_panic: text:ffffffff89ea3cb7 len:2030915468 put:2030915372 head:ffff888058b43000 data:ffff887fdfa6e194 tail:0x120 end:0x6c0 dev:team0 kernel BUG at net/core/skbuff.c:213 ! Oops: invalid opcode: 0000 [#1] SMP KASAN PTI CPU: 1 UID: 0 PID: 1322 Comm: kworker/1:9 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Workqueue: mld mld_ifc_work RIP: 0010:skb_panic+0x157/0x160 net/core/skbuff.c:213 Call Trace: skb_under_panic net/core/skbuff.c:223 [inline] skb_push+0xc3/0xe0 net/core/skbuff.c:2641 ipgre_header+0x67/0x290 net/ipv4/ip_gre.c:897 dev_hard_header include/linux/netdevice.h:3436 [inline] neigh_connected_output+0x286/0x460 net/core/neighbour.c:1618 NF_HOOK_COND include/linux/netfilter.h:307 [inline] ip6_output+0x340/0x550 net/ipv6/ip6_output.c:247 NF_HOOK+0x9e/0x380 include/linux/netfilter.h:318 mld_sendpack+0x8d4/0xe60 net/ipv6/mcast.c:1855 mld_send_cr net/ipv6/mcast.c:2154 [inline] mld_ifc_work+0x83e/0xd60 net/ipv6/mcast.c:2693 process_one_work kernel/workqueue.c:3257 [inline] process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
{
"affected": [],
"aliases": [
"CVE-2026-23011"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-01-25T15:15:55Z",
"severity": "MODERATE"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nipv4: ip_gre: make ipgre_header() robust\n\nAnalog to commit db5b4e39c4e6 (\"ip6_gre: make ip6gre_header() robust\")\n\nOver the years, syzbot found many ways to crash the kernel\nin ipgre_header() [1].\n\nThis involves team or bonding drivers ability to dynamically\nchange their dev-\u003eneeded_headroom and/or dev-\u003ehard_header_len\n\nIn this particular crash mld_newpack() allocated an skb\nwith a too small reserve/headroom, and by the time mld_sendpack()\nwas called, syzbot managed to attach an ipgre device.\n\n[1]\nskbuff: skb_under_panic: text:ffffffff89ea3cb7 len:2030915468 put:2030915372 head:ffff888058b43000 data:ffff887fdfa6e194 tail:0x120 end:0x6c0 dev:team0\n kernel BUG at net/core/skbuff.c:213 !\nOops: invalid opcode: 0000 [#1] SMP KASAN PTI\nCPU: 1 UID: 0 PID: 1322 Comm: kworker/1:9 Not tainted syzkaller #0 PREEMPT(full)\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025\nWorkqueue: mld mld_ifc_work\n RIP: 0010:skb_panic+0x157/0x160 net/core/skbuff.c:213\nCall Trace:\n \u003cTASK\u003e\n skb_under_panic net/core/skbuff.c:223 [inline]\n skb_push+0xc3/0xe0 net/core/skbuff.c:2641\n ipgre_header+0x67/0x290 net/ipv4/ip_gre.c:897\n dev_hard_header include/linux/netdevice.h:3436 [inline]\n neigh_connected_output+0x286/0x460 net/core/neighbour.c:1618\n NF_HOOK_COND include/linux/netfilter.h:307 [inline]\n ip6_output+0x340/0x550 net/ipv6/ip6_output.c:247\n NF_HOOK+0x9e/0x380 include/linux/netfilter.h:318\n mld_sendpack+0x8d4/0xe60 net/ipv6/mcast.c:1855\n mld_send_cr net/ipv6/mcast.c:2154 [inline]\n mld_ifc_work+0x83e/0xd60 net/ipv6/mcast.c:2693\n process_one_work kernel/workqueue.c:3257 [inline]\n process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340\n worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421\n kthread+0x711/0x8a0 kernel/kthread.c:463\n ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158\n ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246",
"id": "GHSA-5ww3-m3hh-c9fg",
"modified": "2026-07-14T15:31:33Z",
"published": "2026-01-25T15:30:27Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-23011"
},
{
"type": "WEB",
"url": "https://cert-portal.siemens.com/productcert/html/ssa-019113.html"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/06fe0801396a36cab865b34f666de1d65bc5ce8e"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/2ecf0aa7cc262472a9599cc51ba02ada0897a17a"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/554201ed0a8f4d32e719f42caeaeb2735a9ed6ca"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/8d5b6b2d79c1c22a5b0db1187a6439dff375a022"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/aa57bfea4674e6da8104fa3a37760a6f5f255dad"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/e67c577d89894811ce4dcd1a9ed29d8b63476667"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/eeb9a521de40c6fadccc12fa5205e5a1b364d5a8"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
]
}
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