{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2023-54193", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-12-30T12:06:44.498Z", "datePublished": "2025-12-30T12:09:00.738Z", "dateUpdated": "2026-08-05T09:17:56.124Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T09:17:56.124Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: cls_api: remove block_cb from driver_list before freeing\n\nError handler of tcf_block_bind() frees the whole bo->cb_list on error.\nHowever, by that time the flow_block_cb instances are already in the driver\nlist because driver ndo_setup_tc() callback is called before that up the\ncall chain in tcf_block_offload_cmd(). This leaves dangling pointers to\nfreed objects in the list and causes use-after-free[0]. Fix it by also\nremoving flow_block_cb instances from driver_list before deallocating them.\n\n[0]:\n[ 279.868433] ==================================================================\n[ 279.869964] BUG: KASAN: slab-use-after-free in flow_block_cb_setup_simple+0x631/0x7c0\n[ 279.871527] Read of size 8 at addr ffff888147e2bf20 by task tc/2963\n\n[ 279.873151] CPU: 6 PID: 2963 Comm: tc Not tainted 6.3.0-rc6+ #4\n[ 279.874273] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014\n[ 279.876295] Call Trace:\n[ 279.876882] \n[ 279.877413] dump_stack_lvl+0x33/0x50\n[ 279.878198] print_report+0xc2/0x610\n[ 279.878987] ? flow_block_cb_setup_simple+0x631/0x7c0\n[ 279.879994] kasan_report+0xae/0xe0\n[ 279.880750] ? flow_block_cb_setup_simple+0x631/0x7c0\n[ 279.881744] ? mlx5e_tc_reoffload_flows_work+0x240/0x240 [mlx5_core]\n[ 279.883047] flow_block_cb_setup_simple+0x631/0x7c0\n[ 279.884027] tcf_block_offload_cmd.isra.0+0x189/0x2d0\n[ 279.885037] ? tcf_block_setup+0x6b0/0x6b0\n[ 279.885901] ? mutex_lock+0x7d/0xd0\n[ 279.886669] ? __mutex_unlock_slowpath.constprop.0+0x2d0/0x2d0\n[ 279.887844] ? ingress_init+0x1c0/0x1c0 [sch_ingress]\n[ 279.888846] tcf_block_get_ext+0x61c/0x1200\n[ 279.889711] ingress_init+0x112/0x1c0 [sch_ingress]\n[ 279.890682] ? clsact_init+0x2b0/0x2b0 [sch_ingress]\n[ 279.891701] qdisc_create+0x401/0xea0\n[ 279.892485] ? qdisc_tree_reduce_backlog+0x470/0x470\n[ 279.893473] tc_modify_qdisc+0x6f7/0x16d0\n[ 279.894344] ? tc_get_qdisc+0xac0/0xac0\n[ 279.895213] ? mutex_lock+0x7d/0xd0\n[ 279.896005] ? __mutex_lock_slowpath+0x10/0x10\n[ 279.896910] rtnetlink_rcv_msg+0x5fe/0x9d0\n[ 279.897770] ? rtnl_calcit.isra.0+0x2b0/0x2b0\n[ 279.898672] ? __sys_sendmsg+0xb5/0x140\n[ 279.899494] ? do_syscall_64+0x3d/0x90\n[ 279.900302] ? entry_SYSCALL_64_after_hwframe+0x46/0xb0\n[ 279.901337] ? kasan_save_stack+0x2e/0x40\n[ 279.902177] ? kasan_save_stack+0x1e/0x40\n[ 279.903058] ? kasan_set_track+0x21/0x30\n[ 279.903913] ? kasan_save_free_info+0x2a/0x40\n[ 279.904836] ? ____kasan_slab_free+0x11a/0x1b0\n[ 279.905741] ? kmem_cache_free+0x179/0x400\n[ 279.906599] netlink_rcv_skb+0x12c/0x360\n[ 279.907450] ? rtnl_calcit.isra.0+0x2b0/0x2b0\n[ 279.908360] ? netlink_ack+0x1550/0x1550\n[ 279.909192] ? rhashtable_walk_peek+0x170/0x170\n[ 279.910135] ? kmem_cache_alloc_node+0x1af/0x390\n[ 279.911086] ? _copy_from_iter+0x3d6/0xc70\n[ 279.912031] netlink_unicast+0x553/0x790\n[ 279.912864] ? netlink_attachskb+0x6a0/0x6a0\n[ 279.913763] ? netlink_recvmsg+0x416/0xb50\n[ 279.914627] netlink_sendmsg+0x7a1/0xcb0\n[ 279.915473] ? netlink_unicast+0x790/0x790\n[ 279.916334] ? iovec_from_user.part.0+0x4d/0x220\n[ 279.917293] ? netlink_unicast+0x790/0x790\n[ 279.918159] sock_sendmsg+0xc5/0x190\n[ 279.918938] ____sys_sendmsg+0x535/0x6b0\n[ 279.919813] ? import_iovec+0x7/0x10\n[ 279.920601] ? kernel_sendmsg+0x30/0x30\n[ 279.921423] ? __copy_msghdr+0x3c0/0x3c0\n[ 279.922254] ? import_iovec+0x7/0x10\n[ 279.923041] ___sys_sendmsg+0xeb/0x170\n[ 279.923854] ? copy_msghdr_from_user+0x110/0x110\n[ 279.924797] ? ___sys_recvmsg+0xd9/0x130\n[ 279.925630] ? __perf_event_task_sched_in+0x183/0x470\n[ 279.926656] ? ___sys_sendmsg+0x170/0x170\n[ 279.927529] ? ctx_sched_in+0x530/0x530\n[ 279.928369] ? update_curr+0x283/0x4f0\n[ 279.929185] ? perf_event_update_userpage+0x570/0x570\n[ 279.930201] ? __fget_light+0x57/0x520\n[ 279.931023] ? __switch_to+0x53d/0xe70\n[ 27\n---truncated---" } ], "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 reached through the tc/rtnetlink qdisc-configuration path (RTM_NEWQDISC via netlink sendmsg), which requires local system access, not a network peer.\nAC:L - The attacker controls every tc operation needed to set up the failing reoffload and trigger the error path, and there is no uncontrolled race; on a common offload-capable NIC the sequence is reliably reproducible.\nPR:L - Configuring tc qdiscs/blocks requires CAP_NET_ADMIN, which an unprivileged local user can obtain in a new network namespace via unshare -Urn, so only low privilege is needed.\nUI:N - The entire sequence is driven by the attacker's own netlink/tc operations with no victim interaction required.\nS:U - The use-after-free corrupts kernel data within the same kernel security authority; no crossing of a VM/IOMMU/sandbox boundary occurs.\nC:H - The dangling driver_list pointer references a freed kmalloc-192 object whose contents can be attacker-controlled via heap spraying, enabling disclosure of kernel memory.\nI:H - A use-after-free of a reclaimable heap object provides a write/type-confusion primitive that can be leveraged toward arbitrary memory modification and control-flow hijacking.\nA:H - The use-after-free reliably causes kernel oops/panic (as shown by the KASAN report), resulting in denial of service." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/sched/cls_api.c" ], "versions": [ { "version": "59094b1e5094c7e50a3d2912202fd30b6a1dadf8", "lessThan": "cc5fe387c6294d0471cb7ed064efac97fac65ccc", "status": "affected", "versionType": "git" }, { "version": "59094b1e5094c7e50a3d2912202fd30b6a1dadf8", "lessThan": "7311c8be3755611bf6edea4dfbeb190b4bdd489f", "status": "affected", "versionType": "git" }, { "version": "59094b1e5094c7e50a3d2912202fd30b6a1dadf8", "lessThan": "cb145932fcf6814e7e95e467eb70e7849a845ae9", "status": "affected", "versionType": "git" }, { "version": "59094b1e5094c7e50a3d2912202fd30b6a1dadf8", "lessThan": "55866fe3fded3ce94ac3fc1bb3dfce654282f483", "status": "affected", "versionType": "git" }, { "version": "59094b1e5094c7e50a3d2912202fd30b6a1dadf8", "lessThan": "26aec72429a05e917d574eca0efc5306c63a8862", "status": "affected", "versionType": "git" }, { "version": "59094b1e5094c7e50a3d2912202fd30b6a1dadf8", "lessThan": "7b7a74ed303d532fb73ae4b1697f16a0fea89cd0", "status": "affected", "versionType": "git" }, { "version": "59094b1e5094c7e50a3d2912202fd30b6a1dadf8", "lessThan": "da94a7781fc3c92e7df7832bc2746f4d39bc624e", "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/cls_api.c" ], "versions": [ { "version": "5.3", "status": "affected" }, { "version": "0", "lessThan": "5.3", "status": "unaffected", "versionType": "semver" }, { "version": "5.4.243", "lessThanOrEqual": "5.4.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.180", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.112", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.29", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.2.16", "lessThanOrEqual": "6.2.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.3.3", "lessThanOrEqual": "6.3.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.4", "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": "5.3", "versionEndExcluding": "5.4.243" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.3", "versionEndExcluding": "5.10.180" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.3", "versionEndExcluding": "5.15.112" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.3", "versionEndExcluding": "6.1.29" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.3", "versionEndExcluding": "6.2.16" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.3", "versionEndExcluding": "6.3.3" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.3", "versionEndExcluding": "6.4" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/cc5fe387c6294d0471cb7ed064efac97fac65ccc" }, { "url": "https://git.kernel.org/stable/c/7311c8be3755611bf6edea4dfbeb190b4bdd489f" }, { "url": "https://git.kernel.org/stable/c/cb145932fcf6814e7e95e467eb70e7849a845ae9" }, { "url": "https://git.kernel.org/stable/c/55866fe3fded3ce94ac3fc1bb3dfce654282f483" }, { "url": "https://git.kernel.org/stable/c/26aec72429a05e917d574eca0efc5306c63a8862" }, { "url": "https://git.kernel.org/stable/c/7b7a74ed303d532fb73ae4b1697f16a0fea89cd0" }, { "url": "https://git.kernel.org/stable/c/da94a7781fc3c92e7df7832bc2746f4d39bc624e" } ], "title": "net/sched: cls_api: remove block_cb from driver_list before freeing", "x_generator": { "engine": "bippy-1.2.0" } } } }