{"id":"CVE-2025-21806","revision":"598c4e6ec245432ea65ee7dc1ffa87f6","records":[{"revision":"598c4e6ec245432ea65ee7dc1ffa87f6","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2025-21806","aliases":[],"title":"net: let net.core.dev_weight always be non-zero","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: let net.core.dev_weight always be non-zero\n\nThe following problem was encountered during stability test:\n\n(NULL net_device): NAPI poll function process_backlog+0x0/0x530 \\\n\treturned 1, exceeding its budget of 0.\n------------[ cut here ]------------\nlist_add double add: new=ffff88905f746f48, prev=ffff88905f746f48, \\\n\tnext=ffff88905f746e40.\nWARNING: CPU: 18 PID: 5462 at lib/list_debug.c:35 \\\n\t__list_add_valid_or_report+0xf3/0x130\nCPU: 18 UID: 0 PID: 5462 Comm: ping Kdump: loaded Not tainted 6.13.0-rc7+\nRIP: 0010:__list_add_valid_or_report+0xf3/0x130\nCall Trace:\n? __warn+0xcd/0x250\n? __list_add_valid_or_report+0xf3/0x130\nenqueue_to_backlog+0x923/0x1070\nnetif_rx_internal+0x92/0x2b0\n__netif_rx+0x15/0x170\nloopback_xmit+0x2ef/0x450\ndev_hard_start_xmit+0x103/0x490\n__dev_queue_xmit+0xeac/0x1950\nip_finish_output2+0x6cc/0x1620\nip_output+0x161/0x270\nip_push_pending_frames+0x155/0x1a0\nraw_sendmsg+0xe13/0x1550\n__sys_sendto+0x3bf/0x4e0\n__x64_sys_sendto+0xdc/0x1b0\ndo_syscall_64+0x5b/0x170\nentry_SYSCALL_64_after_hwframe+0x76/0x7e\n\nThe reproduction command is as follows:\n  sysctl -w net.core.dev_weight=0\n  ping 127.0.0.1\n\nThis is because when the napi's weight is set to 0, process_backlog() may\nreturn 0 and clear the NAPI_STATE_SCHED bit of napi->state, causing this\nnapi to be re-polled in net_rx_action() until __do_softirq() times out.\nSince the NAPI_STATE_SCHED bit has been cleared, napi_schedule_rps() can\nbe retriggered in enqueue_to_backlog(), causing this issue.\n\nMaking the napi's weight always non-zero solves this problem.\n\nTriggering this issue requires system-wide admin (setting is\nnot namespaced).","state":0,"publishedAt":"2025-02-27T20:00:58.918+00:00","modifiedAt":"2026-10-15T01:04:33.084+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/core/sysctl_net_core.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"e3876605450979fe52a1a03e7eb78a89bf59e76a\",\n                            \"lessThan\": \"d0e0f9c8218826926d7692980c98236d9f21fd3c\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"e3876605450979fe52a1a03e7eb78a89bf59e76a\",\n                            \"lessThan\": \"c337c08819a4ec49edfdcd8fc46fbee120d8a5b2\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"e3876605450979fe52a1a03e7eb78a89bf59e76a\",\n                            \"lessThan\": \"0e2f1d93d287d544d26f8ff293ea820a8079b9f8\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"e3876605450979fe52a1a03e7eb78a89bf59e76a\",\n                            \"lessThan\": \"5860abbf15eeb61838b5e32e721ba67b0aa84450\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"e3876605450979fe52a1a03e7eb78a89bf59e76a\",\n                            \"lessThan\": \"6ce38b5a6a49e65bad163162a54cb3f104c40b48\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"e3876605450979fe52a1a03e7eb78a89bf59e76a\",\n                            \"lessThan\": \"33e2168788f8fb5cb8bd4f36cb1ef37d1d34dada\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"e3876605450979fe52a1a03e7eb78a89bf59e76a\",\n                            \"lessThan\": \"1489824e5226a26841c70639ebd2d1aed390764b\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"e3876605450979fe52a1a03e7eb78a89bf59e76a\",\n                            \"lessThan\": \"d1f9f79fa2af8e3b45cffdeef66e05833480148a\",\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/core/sysctl_net_core.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"2.6.12\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"2.6.12\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.4.291\",\n                            \"lessThanOrEqual\": \"5.4.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.10.235\",\n                            \"lessThanOrEqual\": \"5.10.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.15.179\",\n                            \"lessThanOrEqual\": \"5.15.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.1.129\",\n                            \"lessThanOrEqual\": \"6.1.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.6.76\",\n                            \"lessThanOrEqual\": \"6.6.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.13\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.13.2\",\n                            \"lessThanOrEqual\": \"6.13.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.14\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[],"references":["https://git.kernel.org/stable/c/d0e0f9c8218826926d7692980c98236d9f21fd3c","https://git.kernel.org/stable/c/c337c08819a4ec49edfdcd8fc46fbee120d8a5b2","https://git.kernel.org/stable/c/0e2f1d93d287d544d26f8ff293ea820a8079b9f8","https://git.kernel.org/stable/c/5860abbf15eeb61838b5e32e721ba67b0aa84450","https://git.kernel.org/stable/c/6ce38b5a6a49e65bad163162a54cb3f104c40b48","https://git.kernel.org/stable/c/33e2168788f8fb5cb8bd4f36cb1ef37d1d34dada","https://git.kernel.org/stable/c/1489824e5226a26841c70639ebd2d1aed390764b","https://git.kernel.org/stable/c/d1f9f79fa2af8e3b45cffdeef66e05833480148a"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2025-21806","license":"CVE Program Terms of Use","key":"cve-program:CVE-2025-21806","identifiers":["CVE-2025-21806"]},"retained":false,"historicalAffected":[]}],"coverage":[]}