{"id":"CVE-2026-98622","state":"PUBLISHED","title":"net/sched: act_ct: don't WARN on benign flow_offload_alloc() failure","description":"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.","publishedAt":"2026-10-18T15:19:42.514Z","updatedAt":"2026-10-19T09:22:50.359Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"64ff70b80fd403110b67dd9f7184a604fdb0da43","status":"affected","lessThan":"e8fcf3f08834e939b797311742ee72b1e2a08096","versionType":"git"},{"version":"64ff70b80fd403110b67dd9f7184a604fdb0da43","status":"affected","lessThan":"af475f599270e59313552e6c6f3af8507da672b8","versionType":"git"},{"version":"64ff70b80fd403110b67dd9f7184a604fdb0da43","status":"affected","lessThan":"424ba52c0058deeb940d02cba52eb0aeb288db33","versionType":"git"},{"version":"64ff70b80fd403110b67dd9f7184a604fdb0da43","status":"affected","lessThan":"d512c484bd93a5f2794aa03c9faeb7bcb82dbd4a","versionType":"git"},{"version":"64ff70b80fd403110b67dd9f7184a604fdb0da43","status":"affected","lessThan":"d805560ad69cb266d669341ca01e26bffb0d2c67","versionType":"git"},{"version":"64ff70b80fd403110b67dd9f7184a604fdb0da43","status":"affected","lessThan":"00734f3684fcec42c319bedfe68a5d357c720b53","versionType":"git"},{"version":"64ff70b80fd403110b67dd9f7184a604fdb0da43","status":"affected","lessThan":"650787233c2fd6e515a7c5f371019a9fa080ccd2","versionType":"git"},{"version":"64ff70b80fd403110b67dd9f7184a604fdb0da43","status":"affected","lessThan":"47abe7a5c4eb53269aca3506446f851572a059a3","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sched/act_ct.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.7","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.7","versionType":"semver"},{"version":"5.10.271","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.222","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.189","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.158","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.112","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.55","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.9","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sched/act_ct.c"]}],"references":["https://git.kernel.org/stable/c/e8fcf3f08834e939b797311742ee72b1e2a08096","https://git.kernel.org/stable/c/af475f599270e59313552e6c6f3af8507da672b8","https://git.kernel.org/stable/c/424ba52c0058deeb940d02cba52eb0aeb288db33","https://git.kernel.org/stable/c/d512c484bd93a5f2794aa03c9faeb7bcb82dbd4a","https://git.kernel.org/stable/c/d805560ad69cb266d669341ca01e26bffb0d2c67","https://git.kernel.org/stable/c/00734f3684fcec42c319bedfe68a5d357c720b53","https://git.kernel.org/stable/c/650787233c2fd6e515a7c5f371019a9fa080ccd2","https://git.kernel.org/stable/c/47abe7a5c4eb53269aca3506446f851572a059a3"],"weaknesses":[],"ingestedAt":"2026-10-29T20:13:43.249Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/98xxx/CVE-2026-98622.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-98622","state":"PUBLISHED","datePublished":"2026-10-18T15:19:42.514Z","dateUpdated":"2026-10-19T09:22:50.359Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-25T10:25:14.360Z"},"containers":{"cna":{"title":"net/sched: act_ct: don't WARN on benign flow_offload_alloc() failure","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"64ff70b80fd403110b67dd9f7184a604fdb0da43","status":"affected","lessThan":"e8fcf3f08834e939b797311742ee72b1e2a08096","versionType":"git"},{"version":"64ff70b80fd403110b67dd9f7184a604fdb0da43","status":"affected","lessThan":"af475f599270e59313552e6c6f3af8507da672b8","versionType":"git"},{"version":"64ff70b80fd403110b67dd9f7184a604fdb0da43","status":"affected","lessThan":"424ba52c0058deeb940d02cba52eb0aeb288db33","versionType":"git"},{"version":"64ff70b80fd403110b67dd9f7184a604fdb0da43","status":"affected","lessThan":"d512c484bd93a5f2794aa03c9faeb7bcb82dbd4a","versionType":"git"},{"version":"64ff70b80fd403110b67dd9f7184a604fdb0da43","status":"affected","lessThan":"d805560ad69cb266d669341ca01e26bffb0d2c67","versionType":"git"},{"version":"64ff70b80fd403110b67dd9f7184a604fdb0da43","status":"affected","lessThan":"00734f3684fcec42c319bedfe68a5d357c720b53","versionType":"git"},{"version":"64ff70b80fd403110b67dd9f7184a604fdb0da43","status":"affected","lessThan":"650787233c2fd6e515a7c5f371019a9fa080ccd2","versionType":"git"},{"version":"64ff70b80fd403110b67dd9f7184a604fdb0da43","status":"affected","lessThan":"47abe7a5c4eb53269aca3506446f851572a059a3","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sched/act_ct.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.7","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.7","versionType":"semver"},{"version":"5.10.271","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.222","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.189","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.158","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.112","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.55","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.9","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sched/act_ct.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/e8fcf3f08834e939b797311742ee72b1e2a08096"},{"url":"https://git.kernel.org/stable/c/af475f599270e59313552e6c6f3af8507da672b8"},{"url":"https://git.kernel.org/stable/c/424ba52c0058deeb940d02cba52eb0aeb288db33"},{"url":"https://git.kernel.org/stable/c/d512c484bd93a5f2794aa03c9faeb7bcb82dbd4a"},{"url":"https://git.kernel.org/stable/c/d805560ad69cb266d669341ca01e26bffb0d2c67"},{"url":"https://git.kernel.org/stable/c/00734f3684fcec42c319bedfe68a5d357c720b53"},{"url":"https://git.kernel.org/stable/c/650787233c2fd6e515a7c5f371019a9fa080ccd2"},{"url":"https://git.kernel.org/stable/c/47abe7a5c4eb53269aca3506446f851572a059a3"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-19T09:22:50.359Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.7","versionEndExcluding":"5.10.271"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.7","versionEndExcluding":"5.15.222"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.7","versionEndExcluding":"6.1.189"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.7","versionEndExcluding":"6.6.158"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.7","versionEndExcluding":"6.12.112"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.7","versionEndExcluding":"6.18.55"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.7","versionEndExcluding":"7.2.9"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.7","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}