{"cve":"CVE-2026-23011","nvd":{"published":"2026-01-25T15:15:55.977","modified":"2026-10-19T19:17:32.570","status":"Modified","description":"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->needed_headroom and/or dev->hard_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 <TASK>\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","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":["CWE-119"],"references":["https://git.kernel.org/stable/c/06fe0801396a36cab865b34f666de1d65bc5ce8e","https://git.kernel.org/stable/c/2ecf0aa7cc262472a9599cc51ba02ada0897a17a","https://git.kernel.org/stable/c/554201ed0a8f4d32e719f42caeaeb2735a9ed6ca","https://git.kernel.org/stable/c/8d5b6b2d79c1c22a5b0db1187a6439dff375a022","https://git.kernel.org/stable/c/aa57bfea4674e6da8104fa3a37760a6f5f255dad"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-21T03:43:09.190223697+00:00"},"epss":{"cve":"CVE-2026-23011","score":0.0021,"percentile":0.11077,"date":"2026-10-25"},"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."]}