{"id":"CVE-2026-23095","title":"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","summary":"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() retu…","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","cwe":["CWE-401"],"vendor":"linux","product":"linux_kernel","affected":["linux_kernel >= 3.18, < 5.10.249","linux_kernel >= 5.11, < 5.15.199","linux_kernel >= 5.16, < 6.1.162","linux_kernel >= 6.2, < 6.6.122","linux_kernel >= 6.7, < 6.12.68","linux_kernel >= 6.13, < 6.18.8","linux_kernel = 6.19"],"patched":["linux_kernel 6.18.8"],"published":"2026-02-04","updated":"2026-10-15","sourceUpdated":"2026-10-15T02:18:41.837","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-23095","references":[{"url":"https://git.kernel.org/stable/c/380a82d36e37db49fd41ecc378c22fd29392e96a","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/536f5bbc322eb1e175bdd1ced22b236a951c4d8f","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/5437a279804ced8088cabb945dba88a26d828f8c","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/886f186328b718400dbf79e1bc8cbcbd710ab766","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/9a56796ad258786d3624eef5aefba394fc9bdded","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/ce569b389a5c78d64788a5ea94560e17fa574b35","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/f87b9b7a618c82e7465e872eb10e14c803871892","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-019113.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-457936.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"}],"tags":["nvd","cve.org"],"epss":0.00299,"epssPercentile":0.22409,"ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"partial","timestamp":"2026-06-16T20:19:57.582925Z"},"ingestedAt":"2026-09-08T15:33:26.993Z","slug":"CVE-2026-23095","body":"## Overview\n\nIn 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->proto_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\n\n## Affected\n\n- `linux_kernel >= 3.18, < 5.10.249`\n- `linux_kernel >= 5.11, < 5.15.199`\n- `linux_kernel >= 5.16, < 6.1.162`\n- `linux_kernel >= 6.2, < 6.6.122`\n- `linux_kernel >= 6.7, < 6.12.68`\n- `linux_kernel >= 6.13, < 6.18.8`\n- `linux_kernel = 6.19`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `linux_kernel 6.18.8`","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":41.3,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}