{"id":"CVE-2026-98851","state":"PUBLISHED","title":"netfilter: nft_flow_offload: drop flowtable reference on init error path","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nft_flow_offload: drop flowtable reference on init error path\n\nnft_flow_offload_init() bumps the flowtable use count with\nnft_use_inc() before calling nf_ct_netns_get().  When the latter\nfails, the error is returned as-is and the reference is leaked.\n\nThe upper layers do not balance it either: nf_tables_newexpr()\nclears expr->ops when the expression init callback fails, so the\nnft_expr_more() iteration in nft_rule_expr_deactivate() and\nnf_tables_rule_destroy() stops right before the failed expression\nand its ->destroy callback, which would drop the reference, never\nruns.\n\nEach failed rule addition therefore leaks one flowtable reference\nand the flowtable can no longer be removed: NFT_MSG_DELFLOWTABLE\nkeeps reporting -EBUSY even though no rule references it.\n\nSave the nf_ct_netns_get() return value and undo the nft_use_inc()\nwhen it fails, restoring the inc/dec pairing within\nnft_flow_offload_init() itself.","publishedAt":"2026-10-18T15:50:50.910Z","updatedAt":"2026-10-30T12:40:13.069Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"a3c90f7a2323b331ae816d5b0633e68148e25d04","status":"affected","lessThan":"4e5a6d89083af6f23f0ac2cb611ef267590a3ece","versionType":"git"},{"version":"a3c90f7a2323b331ae816d5b0633e68148e25d04","status":"affected","lessThan":"1f43b6b099fa39032780b9494cedfd98f318f3c4","versionType":"git"},{"version":"a3c90f7a2323b331ae816d5b0633e68148e25d04","status":"affected","lessThan":"87f4914758f2da10b56cdb7f90ed815ade1e8ea3","versionType":"git"},{"version":"a3c90f7a2323b331ae816d5b0633e68148e25d04","status":"affected","lessThan":"1d27214fd9a4d2c0c6d998fc9d4fb61448a3438e","versionType":"git"},{"version":"a3c90f7a2323b331ae816d5b0633e68148e25d04","status":"affected","lessThan":"64ac0cb574c740bf723affb79b646eeba920db6b","versionType":"git"},{"version":"a3c90f7a2323b331ae816d5b0633e68148e25d04","status":"affected","lessThan":"c5f91098edee98c015f78488460a0609e62582a5","versionType":"git"},{"version":"a3c90f7a2323b331ae816d5b0633e68148e25d04","status":"affected","lessThan":"4cd378423a33194a773c267fc58606d28fce95cf","versionType":"git"},{"version":"a3c90f7a2323b331ae816d5b0633e68148e25d04","status":"affected","lessThan":"747928b5d4ff8c8de55138a54c13980e4bb88578","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/netfilter/nft_flow_offload.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.16","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.16","versionType":"semver"},{"version":"5.10.273","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.224","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.113","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.56","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.10","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/netfilter/nft_flow_offload.c"]}],"references":["https://git.kernel.org/stable/c/4e5a6d89083af6f23f0ac2cb611ef267590a3ece","https://git.kernel.org/stable/c/1f43b6b099fa39032780b9494cedfd98f318f3c4","https://git.kernel.org/stable/c/87f4914758f2da10b56cdb7f90ed815ade1e8ea3","https://git.kernel.org/stable/c/1d27214fd9a4d2c0c6d998fc9d4fb61448a3438e","https://git.kernel.org/stable/c/64ac0cb574c740bf723affb79b646eeba920db6b","https://git.kernel.org/stable/c/c5f91098edee98c015f78488460a0609e62582a5","https://git.kernel.org/stable/c/4cd378423a33194a773c267fc58606d28fce95cf","https://git.kernel.org/stable/c/747928b5d4ff8c8de55138a54c13980e4bb88578"],"weaknesses":[],"ingestedAt":"2026-10-30T13:00:06.648Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/98xxx/CVE-2026-98851.json","commit":"cb14bf1b43b0c9f05f7f40eae2246263fd430780","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-98851","state":"PUBLISHED","datePublished":"2026-10-18T15:50:50.910Z","dateUpdated":"2026-10-30T12:40:13.069Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-25T10:25:14.376Z"},"containers":{"cna":{"title":"netfilter: nft_flow_offload: drop flowtable reference on init error path","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nft_flow_offload: drop flowtable reference on init error path\n\nnft_flow_offload_init() bumps the flowtable use count with\nnft_use_inc() before calling nf_ct_netns_get().  When the latter\nfails, the error is returned as-is and the reference is leaked.\n\nThe upper layers do not balance it either: nf_tables_newexpr()\nclears expr->ops when the expression init callback fails, so the\nnft_expr_more() iteration in nft_rule_expr_deactivate() and\nnf_tables_rule_destroy() stops right before the failed expression\nand its ->destroy callback, which would drop the reference, never\nruns.\n\nEach failed rule addition therefore leaks one flowtable reference\nand the flowtable can no longer be removed: NFT_MSG_DELFLOWTABLE\nkeeps reporting -EBUSY even though no rule references it.\n\nSave the nf_ct_netns_get() return value and undo the nft_use_inc()\nwhen it fails, restoring the inc/dec pairing within\nnft_flow_offload_init() itself."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"a3c90f7a2323b331ae816d5b0633e68148e25d04","status":"affected","lessThan":"4e5a6d89083af6f23f0ac2cb611ef267590a3ece","versionType":"git"},{"version":"a3c90f7a2323b331ae816d5b0633e68148e25d04","status":"affected","lessThan":"1f43b6b099fa39032780b9494cedfd98f318f3c4","versionType":"git"},{"version":"a3c90f7a2323b331ae816d5b0633e68148e25d04","status":"affected","lessThan":"87f4914758f2da10b56cdb7f90ed815ade1e8ea3","versionType":"git"},{"version":"a3c90f7a2323b331ae816d5b0633e68148e25d04","status":"affected","lessThan":"1d27214fd9a4d2c0c6d998fc9d4fb61448a3438e","versionType":"git"},{"version":"a3c90f7a2323b331ae816d5b0633e68148e25d04","status":"affected","lessThan":"64ac0cb574c740bf723affb79b646eeba920db6b","versionType":"git"},{"version":"a3c90f7a2323b331ae816d5b0633e68148e25d04","status":"affected","lessThan":"c5f91098edee98c015f78488460a0609e62582a5","versionType":"git"},{"version":"a3c90f7a2323b331ae816d5b0633e68148e25d04","status":"affected","lessThan":"4cd378423a33194a773c267fc58606d28fce95cf","versionType":"git"},{"version":"a3c90f7a2323b331ae816d5b0633e68148e25d04","status":"affected","lessThan":"747928b5d4ff8c8de55138a54c13980e4bb88578","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/netfilter/nft_flow_offload.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.16","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.16","versionType":"semver"},{"version":"5.10.273","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.224","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.113","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.56","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.10","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/netfilter/nft_flow_offload.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/4e5a6d89083af6f23f0ac2cb611ef267590a3ece"},{"url":"https://git.kernel.org/stable/c/1f43b6b099fa39032780b9494cedfd98f318f3c4"},{"url":"https://git.kernel.org/stable/c/87f4914758f2da10b56cdb7f90ed815ade1e8ea3"},{"url":"https://git.kernel.org/stable/c/1d27214fd9a4d2c0c6d998fc9d4fb61448a3438e"},{"url":"https://git.kernel.org/stable/c/64ac0cb574c740bf723affb79b646eeba920db6b"},{"url":"https://git.kernel.org/stable/c/c5f91098edee98c015f78488460a0609e62582a5"},{"url":"https://git.kernel.org/stable/c/4cd378423a33194a773c267fc58606d28fce95cf"},{"url":"https://git.kernel.org/stable/c/747928b5d4ff8c8de55138a54c13980e4bb88578"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-30T12:40:13.069Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.16","versionEndExcluding":"5.10.273"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.16","versionEndExcluding":"5.15.224"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.16","versionEndExcluding":"6.1.191"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.16","versionEndExcluding":"6.6.160"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.16","versionEndExcluding":"6.12.113"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.16","versionEndExcluding":"6.18.56"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.16","versionEndExcluding":"7.2.10"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.16","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}