{"id":"CVE-2026-98622","summary":"net/sched: act_ct: don't WARN on benign flow_offload_alloc() failure","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: act_ct: don't WARN on benign flow_offload_alloc() failure\n\nflow_offload_alloc() returns NULL when the conntrack entry is dying\n(e.g. raced with a conntrack flush) or when the GFP_ATOMIC allocation\nfails; both are expected under load and neither is a kernel bug. This\npath runs from softirq on every committed packet, so with\npanic_on_warn=1 an unprivileged user can panic the box just by racing\na conntrack flush against a `tc ... action ct commit` classifier.\n\nReproduced with a custom repro under QEMU: a small, fixed set of UDP\nflows through `tc filter ... action ct commit` on lo, raced against\nthreads flooding bare ctnetlink CT_DELETE (flush) requests. Hits\nWARNING: net/sched/act_ct.c:437 (tcf_ct_flow_table_add(), inlined\ninto tcf_ct_act() in this build) within ~15s on the unpatched kernel;\nsame setup is clean on the patched kernel. The fix itself is\nbehavior-preserving: both branches already did `goto err_alloc`\nbefore and after, only the WARN is removed.","modified":"2026-10-20T02:30:27.716602517Z","published":"2026-10-18T15:19:42.514Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98622.json","cna_assigner":"Linux"},"references":[{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"},{"type":"WEB","url":"https://git.kernel.org/stable/c/00734f3684fcec42c319bedfe68a5d357c720b53"},{"type":"WEB","url":"https://git.kernel.org/stable/c/424ba52c0058deeb940d02cba52eb0aeb288db33"},{"type":"WEB","url":"https://git.kernel.org/stable/c/47abe7a5c4eb53269aca3506446f851572a059a3"},{"type":"WEB","url":"https://git.kernel.org/stable/c/650787233c2fd6e515a7c5f371019a9fa080ccd2"},{"type":"WEB","url":"https://git.kernel.org/stable/c/af475f599270e59313552e6c6f3af8507da672b8"},{"type":"WEB","url":"https://git.kernel.org/stable/c/d512c484bd93a5f2794aa03c9faeb7bcb82dbd4a"},{"type":"WEB","url":"https://git.kernel.org/stable/c/d805560ad69cb266d669341ca01e26bffb0d2c67"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e8fcf3f08834e939b797311742ee72b1e2a08096"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98622.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98622"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"64ff70b80fd403110b67dd9f7184a604fdb0da43"},{"fixed":"e8fcf3f08834e939b797311742ee72b1e2a08096"},{"fixed":"af475f599270e59313552e6c6f3af8507da672b8"},{"fixed":"424ba52c0058deeb940d02cba52eb0aeb288db33"},{"fixed":"d512c484bd93a5f2794aa03c9faeb7bcb82dbd4a"},{"fixed":"d805560ad69cb266d669341ca01e26bffb0d2c67"},{"fixed":"00734f3684fcec42c319bedfe68a5d357c720b53"},{"fixed":"650787233c2fd6e515a7c5f371019a9fa080ccd2"},{"fixed":"47abe7a5c4eb53269aca3506446f851572a059a3"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98622.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.7.0"},{"fixed":"5.10.271"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.222"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.189"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.158"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.112"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.55"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.2.9"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98622.json"}}],"schema_version":"1.9.0"}