{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-72390", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-09T03:40:39.924Z", "datePublished": "2026-08-15T05:56:19.186Z", "dateUpdated": "2026-08-17T05:43:36.388Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T05:43:36.388Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: sch_teql: Introduce slaves_lock to avoid race condition and UAF\n\nThe teql master->slaves singly linked list is not protected against\nmultiple writes. It can be mod'ed concurently from teql_master_xmit(),\nteql_dequeue(), teql_init() and teql_destroy() without holding any list\nlock or RCU protection.\n\nzdi-disclosures@trendmicro.com has demonstrated that the qdisc is freed\nafter an RCU grace period, but teql_master_xmit() running on another\nCPU can still hold a stale pointer into the list, resulting in a\nslab-use-after-free:\n\nBUG: KASAN: slab-use-after-free in teql_master_xmit+0xf0f/0x16b0\nRead of size 8 at addr ffff888013fb0440 by task poc/332\nFreed 512-byte region [ffff888013fb0400, ffff888013fb0600) (kmalloc-512)\n\nThe fix?\nAdd a per-master slaves_lock spinlock that serializes all mutations of\nmaster->slaves and the NEXT_SLAVE() links in teql_destroy() and\nteql_qdisc_init(). teql_master_xmit() also takes the same slaves_lock\naround those updates.\nAnnotate master->slaves and the per-slave ->next pointer with __rcu and\nuse the appropriate RCU accessors everywhere they are touched:\nrcu_assign_pointer() on the writer side (under slaves_lock),\nrcu_dereference_protected() for the writer-side loads (also under\nslaves_lock), rcu_dereference_bh() for the loads in teql_master_xmit() and\nrtnl_dereference() for the loads in teql_master_open()/teql_master_mtu(),\nwhich run under RTNL.\nPair this with rcu_read_lock_bh()/rcu_read_unlock_bh() around the list\ntraversal in teql_master_xmit(), so that readers either observe a fully\nlinked list or are deferred until the in-flight mutation completes. The two\nearly-return paths in teql_master_xmit() are updated to release the RCU-bh\nread-side critical section before returning, since leaving it held would\ndisable BH on that CPU for good." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - Exploitation requires local rtnetlink tc/qdisc operations (RTM_NEWQDISC/RTM_DELQDISC) to attach or tear down TEQL slaves and local packet injection through teql0 to drive teql_master_xmit/teql_dequeue; remote peers cannot reach these control paths without prior CAP_NET_ADMIN setup.\nAC:L - The attacker controls both sides of the race by concurrently churning TEQL slave qdiscs via netlink teardown/re-add while flooding teql0 to keep teql_master_xmit traversing master->slaves; Trend Micro demonstrated reliable slab-use-after-free under this attacker-driven timing.\nPR:L - Configuring and deleting qdiscs requires CAP_NET_ADMIN, but rtnetlink checks netlink_net_capable() against the network namespace user_ns, so an unprivileged local user can obtain CAP_NET_ADMIN via user/network namespaces (unshare -Urn) without init-namespace root.\nUI:N - No victim interaction is required; the attacker programmatically loads/configures TEQL, starts transmit workers, and races qdisc deletion in parallel to trigger the use-after-free.\nS:U - Impact is kernel memory corruption and potential privilege escalation within the same kernel security domain; it does not inherently cross VM, container host, or IOMMU boundaries without separate further exploitation.\nC:H - Demonstrated slab-use-after-free reads through a stale Qdisc pointer in teql_master_xmit (8-byte read from a freed kmalloc-512 object); UAF on Qdisc structures enables heap spraying and arbitrary kernel memory disclosure.\nI:H - Use-after-free of the Qdisc object allows reallocating attacker-controlled data into the freed slab, corrupting list traversal and adjacent qdisc fields to obtain arbitrary kernel write primitives and potential code execution.\nA:H - The bug causes kernel oops/panic from dereferencing freed Qdisc memory during teql_master_xmit list walks; KASAN confirmed slab-use-after-free, and repeated triggering can deny service on affected systems." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/sched/sch_teql.c" ], "versions": [ { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "03c67781254c574ae7fa75e881239a78473bdf42", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "735567bde7401f82b064f9f107b52ee1bf84ed8c", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "11402e6e18e96df615cbcc58157818dd604b23ff", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "9b7d05cbaa60108642402100efa6aa288dd33023", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "b26aa9d993537a4c3167d8ceead3b7c69c3a0aac", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "e5b811fe793166aecc59b085c1b7c31262ef2316", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/sched/sch_teql.c" ], "versions": [ { "version": "2.6.12", "status": "affected" }, { "version": "0", "lessThan": "2.6.12", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.178", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.145", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.97", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.40", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.5", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "6.1.178" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "6.6.145" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "6.12.97" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "6.18.40" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "7.1.5" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/03c67781254c574ae7fa75e881239a78473bdf42" }, { "url": "https://git.kernel.org/stable/c/735567bde7401f82b064f9f107b52ee1bf84ed8c" }, { "url": "https://git.kernel.org/stable/c/11402e6e18e96df615cbcc58157818dd604b23ff" }, { "url": "https://git.kernel.org/stable/c/9b7d05cbaa60108642402100efa6aa288dd33023" }, { "url": "https://git.kernel.org/stable/c/b26aa9d993537a4c3167d8ceead3b7c69c3a0aac" }, { "url": "https://git.kernel.org/stable/c/e5b811fe793166aecc59b085c1b7c31262ef2316" } ], "title": "net/sched: sch_teql: Introduce slaves_lock to avoid race condition and UAF", "x_generator": { "engine": "bippy-1.2.0" } } } }