{"id":"CVE-2026-98968","aliases":[],"cve":{"records":[{"id":"CVE-2026-98968","source":"Linux","state":"PUBLISHED","reasons":[],"replacements":[],"disputed":false,"unsupportedWhenAssigned":false,"reserved":"2026-09-25T10:25:14.383Z","published":"2026-10-23T12:19:39.236Z","modified":"2026-10-30T12:40:34.695Z"}],"publishers":[{"name":"Linux","role":"CNA","organizationId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","modified":"2026-10-30T12:40:34.695Z"}],"references":[{"url":"https://git.kernel.org/stable/c/423a46053788ec4a021d57e69d66db7f7f550da4","tags":[],"source":"Linux"},{"url":"https://git.kernel.org/stable/c/95114e421196250e3d9662f12df442799477d3c3","tags":[],"source":"Linux"},{"url":"https://git.kernel.org/stable/c/e7183b7d518ce8b3e1f7284f9881d7a87569df14","tags":[],"source":"Linux"},{"url":"https://git.kernel.org/stable/c/181cb48c1e9af6b402567e132f879f89d1c54131","tags":[],"source":"Linux"},{"url":"https://git.kernel.org/stable/c/e7ea63b4195a150604993044ab574d8240f2a399","tags":[],"source":"Linux"},{"url":"https://git.kernel.org/stable/c/afae89de73dd693cfa329580ba0fba63bd3f0a11","tags":[],"source":"Linux"}],"weaknesses":[],"applicability":[{"source":"Linux","statements":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.16","versionEndExcluding":"6.1.191"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.16","versionEndExcluding":"6.6.160"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.16","versionEndExcluding":"6.12.113"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.16","versionEndExcluding":"6.18.57"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.16","versionEndExcluding":"7.2.11"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.16","versionEndExcluding":"7.3"}]}]}]}],"prioritization":[]},"title":"amt: send the relay's General Query directly from the receive path","titleSource":"Linux","descriptionSource":"Linux","description":"In the Linux kernel, the following vulnerability has been resolved:\n\namt: send the relay's General Query directly from the receive path\n\nAn skb queued in a qdisc can outlive the tunnel it references\nthrough a raw pointer in skb->cb. For example, with igmp_qrv set\nto 1 on the relay a tunnel lives for 135s, so a netem delay of\n180s on the amt device outlives it; when the tunnel expires and is\nfreed, the subsequent dequeue triggers a use-after-free in\namt_dev_xmit().\n\n  BUG: KASAN: slab-use-after-free in amt_dev_xmit+0x2763/0x2e20\n  Call Trace:\n   amt_dev_xmit+0x2763/0x2e20 [drivers/net/amt.c:1262]\n   dev_hard_start_xmit+0x22f/0x620\n   sch_direct_xmit+0x12e/0xac0\n   netem_dequeue+0x333/0xc50\n   net_tx_action+0x35c/0xa60\n\namt_send_igmp_gq() and amt_send_mld_gq() are only called from\namt_request_handler(), inside the rcu_read_lock_bh() section of\namt_rcv(). amt_request_handler() already has the tunnel the query is\nfor: it found or created it inside that section. Queuing the query with\ndev_queue_xmit() only leads back into amt_dev_xmit(), which strips the\nEthernet header and calls amt_send_membership_query() for that tunnel.\n\nMake that call directly from the two senders instead, the same way\namt_send_advertisement() transmits from the receive path. The query\nnever waits in a qdisc, the tunnel is only dereferenced inside the\nRCU section that found or created it, and nothing is stored in\nskb->cb, so no lookup or refcount is needed. Remove the query branch\nof amt_dev_xmit(), amt_skb_cb() and struct amt_skb_cb, which have no\nusers left.\n\nBehaviour changes:\n - The relay's own General Queries no longer pass through the amt\n   device's egress path: its qdisc, tc egress (clsact/tcx), the\n   netfilter egress hook and packet taps. They are still visible as\n   UDP on the underlay.\n - A query that is sent successfully is no longer counted as\n   tx_dropped. The old query branch left through the unlock label,\n   which counted every sent query as dropped.\n - A query that reaches amt_dev_xmit() on a relay from elsewhere,\n   such as a userspace querier, is now dropped at the IGMP/MLD type\n   switch. Before, it trusted whatever skb->cb held, and a NULL\n   tunnel hit the WARN_ON(1).","score":8.1,"severity":"high","published":"2026-10-23T12:19:39.236Z","modified":"2026-10-30T12:40:34.695Z","withdrawn":false,"knownExploited":false,"affected":[],"products":[{"vendor":"Linux","name":"Linux","platforms":[],"versions":[{"version":"cbc21dc1cfe949e37b2a54c71511579f1899e8d4","status":"affected","lessThan":"423a46053788ec4a021d57e69d66db7f7f550da4","versionType":"git"},{"version":"cbc21dc1cfe949e37b2a54c71511579f1899e8d4","status":"affected","lessThan":"95114e421196250e3d9662f12df442799477d3c3","versionType":"git"},{"version":"cbc21dc1cfe949e37b2a54c71511579f1899e8d4","status":"affected","lessThan":"e7183b7d518ce8b3e1f7284f9881d7a87569df14","versionType":"git"},{"version":"cbc21dc1cfe949e37b2a54c71511579f1899e8d4","status":"affected","lessThan":"181cb48c1e9af6b402567e132f879f89d1c54131","versionType":"git"},{"version":"cbc21dc1cfe949e37b2a54c71511579f1899e8d4","status":"affected","lessThan":"e7ea63b4195a150604993044ab574d8240f2a399","versionType":"git"},{"version":"cbc21dc1cfe949e37b2a54c71511579f1899e8d4","status":"affected","lessThan":"afae89de73dd693cfa329580ba0fba63bd3f0a11","versionType":"git"}],"defaultStatus":"unaffected","cpes":[],"source":"Linux","url":"https://www.cve.org/CVERecord?id=CVE-2026-98968"},{"vendor":"Linux","name":"Linux","platforms":[],"versions":[{"version":"5.16","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.16","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":"6.18.57","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.11","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"defaultStatus":"affected","cpes":[],"source":"Linux","url":"https://www.cve.org/CVERecord?id=CVE-2026-98968"}],"remediation":[],"references":["https://git.kernel.org/stable/c/423a46053788ec4a021d57e69d66db7f7f550da4","https://git.kernel.org/stable/c/95114e421196250e3d9662f12df442799477d3c3","https://git.kernel.org/stable/c/e7183b7d518ce8b3e1f7284f9881d7a87569df14","https://git.kernel.org/stable/c/181cb48c1e9af6b402567e132f879f89d1c54131","https://git.kernel.org/stable/c/e7ea63b4195a150604993044ab574d8240f2a399","https://git.kernel.org/stable/c/afae89de73dd693cfa329580ba0fba63bd3f0a11"],"sources":[{"name":"CVE","id":"CVE-2026-98968","modified":"2026-10-30T12:40:34.695Z","url":"https://www.cve.org/CVERecord?id=CVE-2026-98968"}],"assessments":[{"source":"Linux","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","score":8.1}],"sourceAffected":[],"observedAt":"2026-10-30T13:10:21.145Z","kev":{"status":"not-listed","checkedAt":"2026-11-14T23:55:31.093Z"},"coverage":[{"source":"NVD","status":"not-checked"},{"source":"GHSA","status":"not-checked"},{"source":"EUVD","status":"not-checked"},{"source":"EPSS","status":"not-checked"}],"evidence":[],"aiSummary":null}