{ "schemaVersion": 1, "attribution": [ { "source": "CISA Known Exploited Vulnerabilities", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog", "licence": "US government work" }, { "source": "GitHub Advisory Database", "url": "https://github.com/advisories", "licence": "CC BY 4.0" }, { "source": "Have I Been Pwned", "url": "https://haveibeenpwned.com/", "licence": "CC BY 4.0" }, { "source": "CVE Program (CVE records)", "url": "https://www.cve.org/Legal/TermsOfUse", "licence": "CVE Terms of Use", "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.", "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy." }, { "source": "FIRST EPSS", "url": "https://www.first.org/epss/", "licence": "free to use; FIRST requests attribution" } ], "record": { "id": "CVE-2026-98968", "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2026-98968", "idYear": 2026, "status": "PUBLISHED", "publishedAt": "2026-10-23T12:19:39.236Z", "updatedAt": "2026-10-23T12:19:39.236Z", "importedAt": "2026-10-24T01:58:41.756Z", "snapshot": { "id": "cve_2026-10-24_midnight_baseline", "at": "2026-10-24T00:00:00.000Z", "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z" }, "facts": { "title": "amt: send the relay's General Query directly from the receive path", "summary": "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).", "affected": [ { "vendor": "Linux", "product": "Linux", "defaultStatus": "unaffected", "versions": [ { "version": "cbc21dc1cfe949e37b2a54c71511579f1899e8d4", "status": "affected", "versionType": "git", "lessThan": "95114e421196250e3d9662f12df442799477d3c3" }, { "version": "cbc21dc1cfe949e37b2a54c71511579f1899e8d4", "status": "affected", "versionType": "git", "lessThan": "e7183b7d518ce8b3e1f7284f9881d7a87569df14" }, { "version": "cbc21dc1cfe949e37b2a54c71511579f1899e8d4", "status": "affected", "versionType": "git", "lessThan": "181cb48c1e9af6b402567e132f879f89d1c54131" }, { "version": "cbc21dc1cfe949e37b2a54c71511579f1899e8d4", "status": "affected", "versionType": "git", "lessThan": "e7ea63b4195a150604993044ab574d8240f2a399" }, { "version": "cbc21dc1cfe949e37b2a54c71511579f1899e8d4", "status": "affected", "versionType": "git", "lessThan": "afae89de73dd693cfa329580ba0fba63bd3f0a11" } ] }, { "vendor": "Linux", "product": "Linux", "defaultStatus": "affected", "versions": [ { "version": "5.16", "status": "affected" }, { "version": "0", "status": "unaffected", "versionType": "semver", "lessThan": "5.16" }, { "version": "6.6.160", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.6.*" }, { "version": "6.12.113", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.12.*" }, { "version": "6.18.57", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.18.*" }, { "version": "7.2.11", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "7.2.*" }, { "version": "7.3", "status": "unaffected", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*" } ] } ] } } }