{"schema":"threatline.record/2","record":{"id":"CVE-2026-98021","aliases":[],"summary":"net: reject oversized tx_queue_len at netlink parse time","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: reject oversized tx_queue_len at netlink parse time\n\nrtnl_create_link() assigns IFLA_TXQLEN directly to dev->tx_queue_len\nwithout going through netif_change_tx_queue_len(), so a device created\nwith \"ip link add ... txqueuelen 500000\" bypasses the S16_MAX cap and\nstill triggers the oversized ring allocations in pfifo_fast, tun and\ntap. The veth peer nest (rtnl_nla_parse_ifinfomsg()) and the\nRTM_NEWLINK-on-existing-device path reach the same sinks.\n\nEnforce the cap in ifla_policy instead: IFLA_TXQLEN becomes\nNLA_POLICY_FULL_RANGE(NLA_U32, &txqlen_range) with\ntxqlen_range = { .min = 0, .max = S16_MAX }. All netlink consumers\nparse against this policy - rtnl_setlink(), rtnl_newlink() (create\nand change), and the veth peer nest - so every netlink path is capped\nat parse time and rejects the attribute with -ERANGE plus a proper\n\"integer out of range\" extack message before any device state is\nmodified (the RTM_SETLINK half-application wart is gone with it).\n\nDocument the bound in the rt-link.yaml netlink spec.\n\nConditions to recreate the bug:\n- CONFIG_NET_SCHED=y, CONFIG_VETH=y, CONFIG_USER_NS=y, CONFIG_NET_NS=y.\n- Unprivileged user in a fresh user+net namespace (unshare -Urn):\n  ip link add v0 txqueuelen 500000 type veth peer name v1\n  -> on the fixed kernel this is rejected with -ERANGE (\"integer out\n  of range\" extack) instead of installing an oversized tx_queue_len\n  that later inflates pfifo_fast/tun/tap ring allocations.\n- ip link set v0 txqueuelen 500000 is likewise rejected at parse time.","categories":["Operating systems"],"product":"Linux","vendor":"Linux","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98021","source_modified_at":"2026-10-21T12:54:05.196Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"Linux","vendor":"Linux","versions":[{"version":"38f7b870d4a6a5d3ec21557e849620cb7d032965","lessThan":"26ee5f99ffe7ab98e635071290eff14192e9e34a","status":"affected","versionType":"git"},{"version":"38f7b870d4a6a5d3ec21557e849620cb7d032965","lessThan":"45ca9f59b6c7ea70e0a17054902b8a556913db34","status":"affected","versionType":"git"},{"version":"38f7b870d4a6a5d3ec21557e849620cb7d032965","lessThan":"2fd0880f0272ec022906a05587fd91416ebecc38","status":"affected","versionType":"git"},{"version":"38f7b870d4a6a5d3ec21557e849620cb7d032965","lessThan":"a638a2625aa83160a394abe8e8b2e524a80c771b","status":"affected","versionType":"git"},{"version":"38f7b870d4a6a5d3ec21557e849620cb7d032965","lessThan":"1aa9e143bf51405665a793d4cc925e1c4f0c5922","status":"affected","versionType":"git"}],"defaultStatus":"unaffected"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98021","source_modified_at":"2026-10-21T12:54:05.196Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"Linux","vendor":"Linux","versions":[{"version":"2.6.23","status":"affected"},{"version":"0","lessThan":"2.6.23","status":"unaffected","versionType":"semver"},{"version":"6.6.160","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.111","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.53","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.2.7","lessThanOrEqual":"7.2.*","status":"unaffected","versionType":"semver"},{"version":"7.3","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}],"defaultStatus":"affected"}],"fixed_versions":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98021","source_modified_at":"2026-10-21T12:54:05.196Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"26ee5f99ffe7ab98e635071290eff14192e9e34a","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98021","source_modified_at":"2026-10-21T12:54:05.196Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"45ca9f59b6c7ea70e0a17054902b8a556913db34","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98021","source_modified_at":"2026-10-21T12:54:05.196Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"2fd0880f0272ec022906a05587fd91416ebecc38","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98021","source_modified_at":"2026-10-21T12:54:05.196Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"1aa9e143bf51405665a793d4cc925e1c4f0c5922","basis":"first unaffected version stated in the CVE record"}],"cvss":null,"severity":null,"kev":{"listed":false},"epss":{"probability":0.00176,"percentile":0.0678,"score_date":"2026-10-23"},"published_at":"2026-09-25T10:23:41.505Z","modified_at":"2026-10-21T12:54:05.196Z","provenance":[{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-98021","fetched_at":"2026-10-23T18:45:31.882637Z","source_modified_at":"2026-10-21T12:54:05.196Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-98021","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["CVE List","EPSS"],"references":[{"source":"CVE List","url":"https://git.kernel.org/stable/c/26ee5f99ffe7ab98e635071290eff14192e9e34a"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/45ca9f59b6c7ea70e0a17054902b8a556913db34"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/2fd0880f0272ec022906a05587fd91416ebecc38"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/a638a2625aa83160a394abe8e8b2e524a80c771b"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/1aa9e143bf51405665a793d4cc925e1c4f0c5922"}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":"product","confidence":"heuristic","reviewed":false},"change_timestamp":"2026-10-21T12:54:05.196Z","content_hash":"7bd92a07df4889c6a94c483ad663a8590e81c8c9cc6b42a6790c9e4ac8853030"}}