{"id":"AZL-77136","summary":"CVE-2026-23095 affecting package kernel for versions less than 6.6.126.1-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\ngue: Fix skb memleak with inner IP protocol 0.\n\nsyzbot reported skb memleak below. [0]\n\nThe repro generated a GUE packet with its inner protocol 0.\n\ngue_udp_recv() returns -guehdr-\u003eproto_ctype for \"resubmit\"\nin ip_protocol_deliver_rcu(), but this only works with\nnon-zero protocol number.\n\nLet's drop such packets.\n\nNote that 0 is a valid number (IPv6 Hop-by-Hop Option).\n\nI think it is not practical to encap HOPOPT in GUE, so once\nsomeone starts to complain, we could pass down a resubmit\nflag pointer to distinguish two zeros from the upper layer:\n\n  * no error\n  * resubmit HOPOPT\n\n[0]\nBUG: memory leak\nunreferenced object 0xffff888109695a00 (size 240):\n  comm \"syz.0.17\", pid 6088, jiffies 4294943096\n  hex dump (first 32 bytes):\n    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................\n    00 40 c2 10 81 88 ff ff 00 00 00 00 00 00 00 00  .@..............\n  backtrace (crc a84b336f):\n    kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]\n    slab_post_alloc_hook mm/slub.c:4958 [inline]\n    slab_alloc_node mm/slub.c:5263 [inline]\n    kmem_cache_alloc_noprof+0x3b4/0x590 mm/slub.c:5270\n    __build_skb+0x23/0x60 net/core/skbuff.c:474\n    build_skb+0x20/0x190 net/core/skbuff.c:490\n    __tun_build_skb drivers/net/tun.c:1541 [inline]\n    tun_build_skb+0x4a1/0xa40 drivers/net/tun.c:1636\n    tun_get_user+0xc12/0x2030 drivers/net/tun.c:1770\n    tun_chr_write_iter+0x71/0x120 drivers/net/tun.c:1999\n    new_sync_write fs/read_write.c:593 [inline]\n    vfs_write+0x45d/0x710 fs/read_write.c:686\n    ksys_write+0xa7/0x170 fs/read_write.c:738\n    do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]\n    do_syscall_64+0xa4/0xf80 arch/x86/entry/syscall_64.c:94\n    entry_SYSCALL_64_after_hwframe+0x77/0x7f","modified":"2026-08-28T17:48:02.099904027Z","published":"2026-02-04T17:16:20Z","upstream":["CVE-2026-23095"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-23095"}],"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-77136.json"}}],"schema_version":"1.9.0"}