{"id":"AZL-77121","summary":"CVE-2026-23011 affecting package kernel for versions less than 6.6.126.1-1","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","modified":"2026-08-28T17:45:44.308635077Z","published":"2026-01-25T15:15:55Z","upstream":["CVE-2026-23011"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-23011"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.6.126.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-77121.json"}}],"schema_version":"1.9.0"}