{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2024-57996", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-02-27T02:04:28.914Z", "datePublished": "2025-02-27T02:07:16.765Z", "dateUpdated": "2026-08-05T11:47:15.925Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:47:15.925Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet_sched: sch_sfq: don't allow 1 packet limit\n\nThe current implementation does not work correctly with a limit of\n1. iproute2 actually checks for this and this patch adds the check in\nkernel as well.\n\nThis fixes the following syzkaller reported crash:\n\nUBSAN: array-index-out-of-bounds in net/sched/sch_sfq.c:210:6\nindex 65535 is out of range for type 'struct sfq_head[128]'\nCPU: 0 PID: 2569 Comm: syz-executor101 Not tainted 5.10.0-smp-DEV #1\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024\nCall Trace:\n __dump_stack lib/dump_stack.c:79 [inline]\n dump_stack+0x125/0x19f lib/dump_stack.c:120\n ubsan_epilogue lib/ubsan.c:148 [inline]\n __ubsan_handle_out_of_bounds+0xed/0x120 lib/ubsan.c:347\n sfq_link net/sched/sch_sfq.c:210 [inline]\n sfq_dec+0x528/0x600 net/sched/sch_sfq.c:238\n sfq_dequeue+0x39b/0x9d0 net/sched/sch_sfq.c:500\n sfq_reset+0x13/0x50 net/sched/sch_sfq.c:525\n qdisc_reset+0xfe/0x510 net/sched/sch_generic.c:1026\n tbf_reset+0x3d/0x100 net/sched/sch_tbf.c:319\n qdisc_reset+0xfe/0x510 net/sched/sch_generic.c:1026\n dev_reset_queue+0x8c/0x140 net/sched/sch_generic.c:1296\n netdev_for_each_tx_queue include/linux/netdevice.h:2350 [inline]\n dev_deactivate_many+0x6dc/0xc20 net/sched/sch_generic.c:1362\n __dev_close_many+0x214/0x350 net/core/dev.c:1468\n dev_close_many+0x207/0x510 net/core/dev.c:1506\n unregister_netdevice_many+0x40f/0x16b0 net/core/dev.c:10738\n unregister_netdevice_queue+0x2be/0x310 net/core/dev.c:10695\n unregister_netdevice include/linux/netdevice.h:2893 [inline]\n __tun_detach+0x6b6/0x1600 drivers/net/tun.c:689\n tun_detach drivers/net/tun.c:705 [inline]\n tun_chr_close+0x104/0x1b0 drivers/net/tun.c:3640\n __fput+0x203/0x840 fs/file_table.c:280\n task_work_run+0x129/0x1b0 kernel/task_work.c:185\n exit_task_work include/linux/task_work.h:33 [inline]\n do_exit+0x5ce/0x2200 kernel/exit.c:931\n do_group_exit+0x144/0x310 kernel/exit.c:1046\n __do_sys_exit_group kernel/exit.c:1057 [inline]\n __se_sys_exit_group kernel/exit.c:1055 [inline]\n __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1055\n do_syscall_64+0x6c/0xd0\n entry_SYSCALL_64_after_hwframe+0x61/0xcb\nRIP: 0033:0x7fe5e7b52479\nCode: Unable to access opcode bytes at RIP 0x7fe5e7b5244f.\nRSP: 002b:00007ffd3c800398 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7\nRAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fe5e7b52479\nRDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000000\nRBP: 00007fe5e7bcd2d0 R08: ffffffffffffffb8 R09: 0000000000000014\nR10: 0000000000000000 R11: 0000000000000246 R12: 00007fe5e7bcd2d0\nR13: 0000000000000000 R14: 00007fe5e7bcdd20 R15: 00007fe5e7b24270\n\nThe crash can be also be reproduced with the following (with a tc\nrecompiled to allow for sfq limits of 1):\n\ntc qdisc add dev dummy0 handle 1: root tbf rate 1Kbit burst 100b lat 1s\n../iproute2-6.9.0/tc/tc qdisc add dev dummy0 handle 2: parent 1:10 sfq limit 1\nifconfig dummy0 up\nping -I dummy0 -f -c2 -W0.1 8.8.8.8\nsleep 1\n\nScenario that triggers the crash:\n\n* the first packet is sent and queued in TBF and SFQ; qdisc qlen is 1\n\n* TBF dequeues: it peeks from SFQ which moves the packet to the\n gso_skb list and keeps qdisc qlen set to 1. TBF is out of tokens so\n it schedules itself for later.\n\n* the second packet is sent and TBF tries to queues it to SFQ. qdisc\n qlen is now 2 and because the SFQ limit is 1 the packet is dropped\n by SFQ. At this point qlen is 1, and all of the SFQ slots are empty,\n however q->tail is not NULL.\n\nAt this point, assuming no more packets are queued, when sch_dequeue\nruns again it will decrement the qlen for the current empty slot\ncausing an underflow and the subsequent out of bounds access." } ], "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 vulnerability is triggered by configuring an SFQ qdisc with `limit 1` via RTM_NEWQDISC netlink, which requires local system access. Per kernel scoring guidance, tc/netlink qdisc configuration is Local.\nAC:L - The trigger is fully deterministic and attacker-controlled: attach sfq limit 1 under a peeking parent (tbf), send two packets, then let dequeue/reset run — no race, no unusual config, and sch_sfq autoloads via its netlink module alias.\nPR:L - Qdisc configuration is gated by netlink_net_capable(CAP_NET_ADMIN), which resolves to ns_capable() against the netns owner user namespace, so an unprivileged user obtains it with `unshare -Urn` and a dummy/veth device.\nUI:N - The attacker performs every step — creating the qdisc hierarchy, generating the packets, and triggering the dequeue/reset — with no victim action required.\nS:U - The corruption stays within the kernel's own security authority; there is no crossing of a VM, IOMMU, or hypervisor boundary.\nC:H - The u16 qlen underflow produces an unbounded out-of-bounds read at q->dep[65535] (~256 KB past a slab object), whose value is reused as an index into further accesses, and the fake-skb type confusion exposes adjacent heap contents as skb fields — memory disclosure primitives well beyond a bounded few bytes.\nI:H - sfq_link() performs wild out-of-bounds writes (q->dep[65535].next = x, and sfq_dep_head(q, n)->prev = x with n read from OOB memory), and sfq_reset() frees a type-confused fake skb pointing into the qdisc allocation — a strong heap-corruption/arbitrary-write primitive suitable for control-flow hijack.\nA:H - The bug reliably produces out-of-bounds accesses and a bogus kfree_skb() on a non-skb pointer, causing kernel oops/panic (and a UBSAN splat on hardened builds), repeatable at will by an unprivileged local user." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/sched/sch_sfq.c" ], "versions": [ { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "e12f6013d0a69660e8b99bfe381b9546ae667328", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "1e6d9d87626cf89eeffb4d943db12cb5b10bf961", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "1b562b7f9231432da40d12e19786c1bd7df653a7", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "35d0137305ae2f97260a9047f445bd4434bd6cc7", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "833e9a1c27b82024db7ff5038a51651f48f05e5e", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "7d8947f2153ee9c5ab4cb17861a11cc45f30e8c4", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "7fefc294204f10a3405f175f4ac2be16d63f135e", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "10685681bafce6febb39770f3387621bf5d67d0b", "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_sfq.c" ], "versions": [ { "version": "2.6.12", "status": "affected" }, { "version": "0", "lessThan": "2.6.12", "status": "unaffected", "versionType": "semver" }, { "version": "5.4.297", "lessThanOrEqual": "5.4.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.239", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.186", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.129", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.76", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.13", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.13.2", "lessThanOrEqual": "6.13.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.14", "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": "5.4.297" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "5.10.239" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "5.15.186" }, { "vulnerable": true, "criteria": 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"https://git.kernel.org/stable/c/1b562b7f9231432da40d12e19786c1bd7df653a7" }, { "url": "https://git.kernel.org/stable/c/35d0137305ae2f97260a9047f445bd4434bd6cc7" }, { "url": "https://git.kernel.org/stable/c/833e9a1c27b82024db7ff5038a51651f48f05e5e" }, { "url": "https://git.kernel.org/stable/c/7d8947f2153ee9c5ab4cb17861a11cc45f30e8c4" }, { "url": "https://git.kernel.org/stable/c/7fefc294204f10a3405f175f4ac2be16d63f135e" }, { "url": "https://git.kernel.org/stable/c/10685681bafce6febb39770f3387621bf5d67d0b" } ], "title": "net_sched: sch_sfq: don't allow 1 packet limit", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "title": "CVE Program Container", "references": [ { "url": "https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html" }, { "url": "https://lists.debian.org/debian-lts-announce/2025/03/msg00028.html" } ], "providerMetadata": { "orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2025-11-03T19:33:07.578Z" } }, { "x_adpType": "supplier", "providerMetadata": { "orgId": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e", "shortName": "siemens-SADP", "dateUpdated": "2026-07-14T12:38:48.740Z" }, "affected": [ { "vendor": "Siemens", "product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP", "versions": [ { "status": "affected", "version": "V3.1.5", "lessThan": "*", "versionType": "custom" } ], "defaultStatus": "unknown" }, { "vendor": "Siemens", "product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP", "versions": [ { "status": "affected", "version": "V3.1.5", "lessThan": "*", "versionType": "custom" } ], "defaultStatus": "unknown" }, { "vendor": "Siemens", "product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP", "versions": [ { "status": "affected", "version": "V3.1.5", "lessThan": "*", "versionType": "custom" } ], "defaultStatus": "unknown" }, { "vendor": "Siemens", "product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP", "versions": [ { "status": "affected", "version": "V3.1.5", "lessThan": "*", "versionType": "custom" } ], "defaultStatus": "unknown" }, { "vendor": "Siemens", "product": "SIPLUS S7-1500 CPU 1518-4 PN/DP MFP", "versions": [ { "status": "affected", "version": "V3.1.5", "lessThan": "*", "versionType": "custom" } ], "defaultStatus": "unknown" } ], "references": [ { "url": "https://cert-portal.siemens.com/productcert/html/ssa-082556.html" } ] } ] } }