{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-98369", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-25T10:25:14.344Z", "datePublished": "2026-10-06T08:46:54.188Z", "dateUpdated": "2026-10-19T09:18:21.221Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T09:18:21.221Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: add missing rcu_read_lock(), skb_dst_force() and dev_hold() for xfrm_trans_reinject()\n\nsyzbot reported a suspicious RCU usage warning in ip6_pkt_drop():\n\n WARNING: suspicious RCU usage in ip6_pkt_drop\n include/net/addrconf.h:389 suspicious rcu_dereference_check() usage!\n\n Call Trace:\n __in6_dev_get_safely include/net/addrconf.h:389 [inline]\n ip6_pkt_drop+0x596/0x610 net/ipv6/route.c:4620\n ip6_pkt_discard+0x1c/0x30 net/ipv6/route.c:4651\n xfrm_trans_reinject+0x324/0x630 net/xfrm/xfrm_input.c:806\n process_one_work kernel/workqueue.c:3322 [inline]\n process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405\n worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486\n\nWhen commit 4f4920669d21 (\"xfrm: Reinject transport-mode packets through\nworkqueue\") converted xfrm_trans_reinject from a tasklet to a workqueue,\nthe reinjection loop ceased running in softirq context. Workqueue workers\nrun in process context where local_bh_disable() does not enter an RCU\nread-side critical section under CONFIG_PREEMPT_RCU.\n\nBecause finish callbacks (such as ip6_rcv_finish) expect to run under an\nRCU read lock (performing route lookups, l3mdev lookups, and accessing\nRCU-protected data structures), invoking them in workqueue context without\nrcu_read_lock() triggers RCU lockdep warnings.\n\nFurthermore, packets queued to the workqueue via xfrm_trans_queue_net()\nmay carry non-refcounted (noref) dst entries (e.g. from ip_route_input_noref).\nAdditionally, on netdevice unregistration, dst_dev_put() replaces dst->dev\nwith blackhole_netdev, so dst entries do not keep skb->dev alive while\nqueued in the workqueue.\n\nFix these issues by:\n1. Calling skb_dst_force(skb) in xfrm_trans_queue_net() while still in the\n caller's RCU section to ensure dst is reference-counted before queuing.\n2. Holding a reference on skb->dev via dev_hold()/dev_put() across workqueue\n deferral so skb->dev remains valid during finish() callback processing.\n3. Acquiring rcu_read_lock() around the finish callback invocation loop in\n xfrm_trans_reinject()." } ], "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 - The use-after-free happens only when a queued packet's net_device or noref dst is freed before xfrm_trans_reinject() runs. A remote ESP peer sends the packet but cannot unregister the device or change routes, so the attacker who controls the whole race is local: they create the netns, veth and XFRM SA through xfrm_user netlink.\nAC:L - The attacker does both sides of the race. They send ESP transport-mode packets that xfrm4_transport_finish/xfrm6_transport_finish queue through xfrm_trans_queue(), then delete the veth or route while the workqueue is still behind. Flooding the queue up to max_backlog widens the window.\nPR:L - xfrm_user_rcv_msg checks netlink_net_capable(CAP_NET_ADMIN), which an unprivileged user gets in a new user and network namespace (unshare -Urn). That lets them create the SA, the veth devices and the routes the trigger needs.\nUI:N - No victim action is needed. The attacker sets up the namespace, sends the packets and tears down the device or route themselves.\nS:U - The freed net_device, dst_entry and RCU-protected route data are kernel memory, and the impact stays within the kernel's own security authority.\nC:H - ip6_rcv_finish and dst_input in xfrm_trans_reinject() read a freed skb->dev or noref dst_entry with no reference and no RCU lock. If an attacker reclaims that memory, these use-after-free reads can leak kernel memory.\nI:H - The freed dst_entry holds an input function pointer that dst_input() calls, and net_device is full of ops pointers. Reclaiming either object with attacker-controlled data gives a path to hijacking control flow.\nA:H - A use-after-free of the net_device or dst in the xfrm_trans_reinject worker crashes the kernel, and syzbot hit the missing-RCU path in ip6_pkt_drop. The attacker can trigger it repeatedly." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/xfrm/xfrm_input.c" ], "versions": [ { "version": "7d98b26684cb2390729525b341ea099f0badbe18", "lessThan": "41e47f1664be86c91326f0afe0504a1162d00907", "status": "affected", "versionType": "git" }, { "version": "4f4920669d21e1060b7243e5118dc3b71ced1276", "lessThan": "6601d91a85761f33351c71e04ec0bbd294ca07ce", "status": "affected", "versionType": "git" }, { "version": "4f4920669d21e1060b7243e5118dc3b71ced1276", "lessThan": "0cda8273265d30cac6423834fd7d4acb75f04fdb", "status": "affected", "versionType": "git" }, { "version": "4f4920669d21e1060b7243e5118dc3b71ced1276", "lessThan": "68a317b4aec8ca1868a39d69e40f9e29baa4f40a", "status": "affected", "versionType": "git" }, { "version": "4f4920669d21e1060b7243e5118dc3b71ced1276", "lessThan": "6eb3b071be8e260543c604550c54dac66e6b174b", "status": "affected", "versionType": "git" }, { "version": "4f4920669d21e1060b7243e5118dc3b71ced1276", "lessThan": "664fc0941df7c1918b2cd4de6ee00469ba77d8e4", "status": "affected", "versionType": "git" }, { "version": "4f4920669d21e1060b7243e5118dc3b71ced1276", "lessThan": "d2f5082f9e84653fa1a9e8aebaaff23e688f5e19", "status": "affected", "versionType": "git" }, { "version": "f520075da484306bbb8425afd2c42404ba74816f", "status": "affected", "versionType": "git" }, { "version": "130d9e5017ade1b81d16783563edb38c12a2eab7", "status": "affected", "versionType": "git" }, { "version": "5.15.75", "lessThan": "5.15.222", "status": "affected", "versionType": "semver" }, { "version": "5.19.17", "lessThan": "5.20", "status": "affected", "versionType": "semver" }, { "version": "6.0.3", "lessThan": "6.1", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/xfrm/xfrm_input.c" ], "versions": [ { "version": "6.1", "status": "affected" }, { "version": "0", "lessThan": "6.1", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.222", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.189", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.158", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.112", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.54", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.8", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.3", "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": "5.15.75", "versionEndExcluding": "5.15.222" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.1", "versionEndExcluding": "6.1.189" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.1", "versionEndExcluding": "6.6.158" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.1", "versionEndExcluding": "6.12.112" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.1", "versionEndExcluding": "6.18.54" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.1", "versionEndExcluding": "7.2.8" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.1", "versionEndExcluding": "7.3" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.19.17" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.0.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/41e47f1664be86c91326f0afe0504a1162d00907" }, { "url": "https://git.kernel.org/stable/c/6601d91a85761f33351c71e04ec0bbd294ca07ce" }, { "url": "https://git.kernel.org/stable/c/0cda8273265d30cac6423834fd7d4acb75f04fdb" }, { "url": "https://git.kernel.org/stable/c/68a317b4aec8ca1868a39d69e40f9e29baa4f40a" }, { "url": "https://git.kernel.org/stable/c/6eb3b071be8e260543c604550c54dac66e6b174b" }, { "url": "https://git.kernel.org/stable/c/664fc0941df7c1918b2cd4de6ee00469ba77d8e4" }, { "url": "https://git.kernel.org/stable/c/d2f5082f9e84653fa1a9e8aebaaff23e688f5e19" } ], "title": "xfrm: add missing rcu_read_lock(), skb_dst_force() and dev_hold() for xfrm_trans_reinject()", "x_generator": { "engine": "bippy-1.2.0" } } } }