{"id":"CVE-2026-23011","state":"PUBLISHED","title":"ipv4: ip_gre: make ipgre_header() robust","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","publishedAt":"2026-01-25T14:36:24.455Z","updatedAt":"2026-10-19T18:25:27.814Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"c54419321455631079c7d6e60bc732dd0c5914c5","status":"affected","lessThan":"eeb9a521de40c6fadccc12fa5205e5a1b364d5a8","versionType":"git"},{"version":"c54419321455631079c7d6e60bc732dd0c5914c5","status":"affected","lessThan":"8d5b6b2d79c1c22a5b0db1187a6439dff375a022","versionType":"git"},{"version":"c54419321455631079c7d6e60bc732dd0c5914c5","status":"affected","lessThan":"2ecf0aa7cc262472a9599cc51ba02ada0897a17a","versionType":"git"},{"version":"c54419321455631079c7d6e60bc732dd0c5914c5","status":"affected","lessThan":"06fe0801396a36cab865b34f666de1d65bc5ce8e","versionType":"git"},{"version":"c54419321455631079c7d6e60bc732dd0c5914c5","status":"affected","lessThan":"aa57bfea4674e6da8104fa3a37760a6f5f255dad","versionType":"git"},{"version":"c54419321455631079c7d6e60bc732dd0c5914c5","status":"affected","lessThan":"554201ed0a8f4d32e719f42caeaeb2735a9ed6ca","versionType":"git"},{"version":"c54419321455631079c7d6e60bc732dd0c5914c5","status":"affected","lessThan":"e67c577d89894811ce4dcd1a9ed29d8b63476667","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ipv4/ip_gre.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"3.10","status":"affected"},{"version":"0","status":"unaffected","lessThan":"3.10","versionType":"semver"},{"version":"5.10.249","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.199","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.162","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.122","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.67","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.7","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ipv4/ip_gre.c"]}],"references":["https://git.kernel.org/stable/c/eeb9a521de40c6fadccc12fa5205e5a1b364d5a8","https://git.kernel.org/stable/c/8d5b6b2d79c1c22a5b0db1187a6439dff375a022","https://git.kernel.org/stable/c/2ecf0aa7cc262472a9599cc51ba02ada0897a17a","https://git.kernel.org/stable/c/06fe0801396a36cab865b34f666de1d65bc5ce8e","https://git.kernel.org/stable/c/aa57bfea4674e6da8104fa3a37760a6f5f255dad","https://git.kernel.org/stable/c/554201ed0a8f4d32e719f42caeaeb2735a9ed6ca","https://git.kernel.org/stable/c/e67c577d89894811ce4dcd1a9ed29d8b63476667","https://cert-portal.siemens.com/productcert/html/ssa-019113.html","https://cert-portal.siemens.com/productcert/html/ssa-457936.html"],"weaknesses":["CWE-119"],"ingestedAt":"2026-10-29T20:11:21.040Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/23xxx/CVE-2026-23011.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-23011","state":"PUBLISHED","datePublished":"2026-01-25T14:36:24.455Z","dateUpdated":"2026-10-19T18:25:27.814Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-01-13T15:37:45.939Z"},"containers":{"cna":{"title":"ipv4: ip_gre: make ipgre_header() robust","descriptions":[{"lang":"en","value":"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 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