{ "schema_version": "1.6.1", "id": "RPI-CVE-2026-72035", "modified": "2026-10-09T11:39:44Z", "upstream": [ "CVE-2026-72035" ], "published": "2026-08-15T06:04:33Z", "summary": "net/sched: sch_taprio: Replace direct dequeue call with peek and qdisc_dequeue_peeked", "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: sch_taprio: Replace direct dequeue call with peek and qdisc_dequeue_peeked\n\nWhen taprio's software path peeks a non-work-conserving child qdisc, the\nchild stashes the peeked skb in its gso_skb; taprio_dequeue_from_txq()\nthen takes the packet with a direct child ->dequeue() call, which ignores\nthat stash, orphans the peeked skb and desyncs the child's qlen/backlog.\nWith a qfq child this re-enters the child on an emptied list and\ndereferences NULL, panicking the kernel from softirq on ordinary egress.\n\nTake the packet through qdisc_dequeue_peeked(), as sch_red and sch_sfb\nnow do. The helper returns the child's stashed skb first and is a no-op\nwhen there is none, so a work-conserving child is unaffected and the\ngated path now consumes the skb whose length was charged to the budget.", "severity": [ { "type": "CVSS_V3", "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H" } ], "affected": [ { "package": { "ecosystem": "Raspberry Pi OS:12", "name": "linux" }, "versions": [ "1:6.1.47-1+rpt4" ], "ecosystem_specific": { "binaries": [ { "binary_name": "linux-image-6.1.0-rpi3-rpi-2712", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v6", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v7", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v7l", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v8", "binary_version": "1:6.1.47-1+rpt4" } ] }, "database_specific": { "per_version": { "1:6.1.47-1+rpt4": { "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e", "upstream_version": "6.1.47", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.1.184", "compiled_filter": false } } } } ], "references": [ { "type": "ADVISORY", "url": "https://www.cve.org/CVERecord?id=CVE-2026-72035" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/51f8af240aed903e988755af33d7491030b50ae9" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/17ab5f76f3899f67e5569722f334591f4b88b17b" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/f60d5c12e0551012cee5c272b0bcbcc78f7bb506" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/6ee5a7665a9080bcb05d703bf981a579436fd05e" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/18d580cb00c55805633bae45e90cf22ed6b8e424" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/e2b7ee61989f2d39df6c2cc06f9db1aea69bdb09" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/2dcebbd1ad2e180fe7b98bf346ced69a872e11e6" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/e056e1dfcddca877dd46d704e8ec9860cfc9ec44" } ], "database_specific": { "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git", "upstream_modified": "2026-08-23T12:46:35Z", "severity": { "source": "kernel CNA", "cvss_v3_score": 8.2, "cvss_v3_severity": "High", "scenario": "AV:N - The fault is in taprio's software egress dequeue path (`__dev_queue_xmit` \u2192 `__qdisc_run` \u2192 `taprio_dequeue` \u2192 `taprio_dequeue_from_txq`) during ordinary packet transmission in softirq; on TSN/automotive/industrial gateways where taprio+qfq is already deployed, any remote peer can trigger it by sending traffic that causes egress through the gated queues.\nAC:L - Once taprio is configured with a non-work-conserving child such as qfq on the software path (no full offload, TXTIME_ASSIST disabled), peek followed by the incorrect direct `dequeue()` deterministically orphans the stashed skb, desyncs qlen/backlog, and re-enters qfq on an emptied list; the attacker fully controls triggering traffic with no uncontrollable races.\nPR:N - Installing taprio and grafting a qfq child requires CAP_NET_ADMIN via RTM_NEWQDISC, but on reasonably deployed TSN/industrial systems where operators have already configured this stack, triggering the bug requires only the ability to send packets through the affected interface\u2014no credentials or capabilities on the victim host.\nUI:N - Exploitation needs only attacker-generated network traffic (or any local sender) once the qdisc hierarchy exists; no victim login, mount, file open, or other interactive action is required at trigger time.\nS:U - The NULL dereference kernel panic and qdisc qlen/backlog corruption occur entirely within the host kernel's security authority; this is not a VM escape, container breakout, or IOMMU/DMA boundary bypass.\nC:N - The published failure mode is a NULL pointer dereference in qfq after taprio mishandles the peek stash; although the peeked skb is orphaned and child counters desync, there is no use-after-free, out-of-bounds read, or demonstrated arbitrary kernel memory disclosure primitive.\nI:L - Calling `child->ops->dequeue()` instead of `qdisc_dequeue_peeked()` orphans the peek-stashed skb and corrupts the child qdisc's qlen/backlog accounting before the fatal qfq re-entry, enabling attacker-driven mis-accounting of queued traffic on the affected egress path prior to panic.\nA:H - With a qfq child the desynchronized dequeue path dereferences NULL from softirq during ordinary egress, panicking the kernel; the condition is repeatable whenever gated transmission exercises the peek/dequeue mismatch, causing total host availability loss." } } }