{"id":"CVE-2026-23095","revision":"06d606241f21460884b7a4c70c466fdd","records":[{"revision":"06d606241f21460884b7a4c70c466fdd","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-23095","aliases":[],"title":"gue: Fix skb memleak with inner IP protocol 0.","description":"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->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","state":0,"publishedAt":"2026-02-04T16:08:17.99+00:00","modifiedAt":"2026-10-19T18:25:30.509+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n \"product\": \"Linux\",\n \"vendor\": \"Linux\",\n \"defaultStatus\": \"unaffected\",\n \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n \"programFiles\": [\n \"net/ipv4/fou_core.c\"\n ],\n \"versions\": [\n {\n \"version\": \"37dd0247797b168ad1cc7f5dbec825a1ee66535b\",\n \"lessThan\": \"886f186328b718400dbf79e1bc8cbcbd710ab766\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"37dd0247797b168ad1cc7f5dbec825a1ee66535b\",\n \"lessThan\": \"380a82d36e37db49fd41ecc378c22fd29392e96a\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"37dd0247797b168ad1cc7f5dbec825a1ee66535b\",\n \"lessThan\": \"536f5bbc322eb1e175bdd1ced22b236a951c4d8f\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"37dd0247797b168ad1cc7f5dbec825a1ee66535b\",\n \"lessThan\": \"f87b9b7a618c82e7465e872eb10e14c803871892\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"37dd0247797b168ad1cc7f5dbec825a1ee66535b\",\n \"lessThan\": \"ce569b389a5c78d64788a5ea94560e17fa574b35\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"37dd0247797b168ad1cc7f5dbec825a1ee66535b\",\n \"lessThan\": \"5437a279804ced8088cabb945dba88a26d828f8c\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"37dd0247797b168ad1cc7f5dbec825a1ee66535b\",\n \"lessThan\": \"9a56796ad258786d3624eef5aefba394fc9bdded\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n }\n ]\n }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n \"product\": \"Linux\",\n \"vendor\": \"Linux\",\n \"defaultStatus\": \"affected\",\n \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n \"programFiles\": [\n \"net/ipv4/fou_core.c\"\n ],\n \"versions\": [\n {\n \"version\": \"3.18\",\n \"status\": \"affected\"\n },\n {\n \"version\": \"0\",\n \"lessThan\": \"3.18\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"5.10.249\",\n \"lessThanOrEqual\": \"5.10.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"5.15.199\",\n \"lessThanOrEqual\": \"5.15.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.1.162\",\n \"lessThanOrEqual\": \"6.1.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.6.122\",\n \"lessThanOrEqual\": \"6.6.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.12.68\",\n \"lessThanOrEqual\": \"6.12.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.18.8\",\n \"lessThanOrEqual\": \"6.18.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.19\",\n \"lessThanOrEqual\": \"*\",\n \"status\": \"unaffected\",\n \"versionType\": \"original_commit_for_fix\"\n }\n ]\n }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5,"severity":"HIGH"}],"references":["https://git.kernel.org/stable/c/886f186328b718400dbf79e1bc8cbcbd710ab766","https://git.kernel.org/stable/c/380a82d36e37db49fd41ecc378c22fd29392e96a","https://git.kernel.org/stable/c/536f5bbc322eb1e175bdd1ced22b236a951c4d8f","https://git.kernel.org/stable/c/f87b9b7a618c82e7465e872eb10e14c803871892","https://git.kernel.org/stable/c/ce569b389a5c78d64788a5ea94560e17fa574b35","https://git.kernel.org/stable/c/5437a279804ced8088cabb945dba88a26d828f8c","https://git.kernel.org/stable/c/9a56796ad258786d3624eef5aefba394fc9bdded"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-23095","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-23095","identifiers":["CVE-2026-23095"]},"retained":false,"historicalAffected":[]}],"coverage":[]}