Answer in brief
CVE-2023-54193 records a High severity (CVSS 7.8) vulnerability in net/sched: cls_api: remove block_cb from driver_list before freeing. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 7.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=59094b1e5094c7e50a3d2912202fd30b6a1dadf8 <cc5fe387c6294d0471cb7ed064efac97fac65ccc || >=59094b1e5094c7e50a3d2912202fd30b6a1dadf8 <7311c8be3755611bf6edea4dfbeb190b4bdd489f || >=59094b1e5094c7e50a3d2912202fd30b6a1dadf8 <cb145932fcf6814e7e95e467eb70e7849a845ae9 || >=59094b1e5094c7e50a3d2912202fd30b6a1dadf8 <55866fe3fded3ce94ac3fc1bb3dfce654282f483 || >=59094b1e5094c7e50a3d2912202fd30b6a1dadf8 <26aec72429a05e917d574eca0efc5306c63a8862 || >=59094b1e5094c7e50a3d2912202fd30b6a1dadf8 <7b7a74ed303d532fb73ae4b1697f16a0fea89cd0 || >=59094b1e5094c7e50a3d2912202fd30b6a1dadf8 <da94a7781fc3c92e7df7832bc2746f4d39bc624e | cc5fe387c6294d0471cb7ed064efac97fac65ccc, 7311c8be3755611bf6edea4dfbeb190b4bdd489f, cb145932fcf6814e7e95e467eb70e7849a845ae9, 55866fe3fded3ce94ac3fc1bb3dfce654282f483, 26aec72429a05e917d574eca0efc5306c63a8862, 7b7a74ed303d532fb73ae4b1697f16a0fea89cd0, da94a7781fc3c92e7df7832bc2746f4d39bc624e |
| Linux/Linuxgeneric | 5.3 | Not reported |
Published upstream
Dec 30, 2025
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 28, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 5, 2026
In the Linux kernel, the following vulnerability has been resolved: net/sched: cls_api: remove block_cb from driver_list before freeing Error handler of tcf_block_bind() frees the whole bo->cb_list on error. However, by that time the flow_block_cb instances are already in the driver list because driver ndo_setup_tc() callback is called before that up the call chain in tcf_block_offload_cmd(). This leaves dangling pointers to freed objects in the list and causes use-after-free[0]. Fix it by also removing flow_block_cb instances from driver_list before deallocating them. [0]: [ 279.868433] ================================================================== [ 279.869964] BUG: KASAN: slab-use-after-free in flow_block_cb_setup_simple+0x631/0x7c0 [ 279.871527] Read of size 8 at addr ffff888147e2bf20 by task tc/2963 [ 279.873151] CPU: 6 PID: 2963 Comm: tc Not tainted 6.3.0-rc6+ #4 [ 279.874273] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 [ 279.876295] Call Trace: [ 279.876882] <TASK> [ 279.877413] dump_stack_lvl+0x33/0x50 [ 279.878198] print_report+0xc2/0x610 [ 279.878987] ? flow_block_cb_setup_simple+0x631/0x7c0 [ 279.879994] kasan_report+0xae/0xe0 [ 279.880750] ? flow_block_cb_setup_simple+0x631/0x7c0 [ 279.881744] ? mlx5e_tc_reoffload_flows_work+0x240/0x240 [mlx5_core] [ 279.883047] flow_block_cb_setup_simple+0x631/0x7c0 [ 279.884027] tcf_block_offload_cmd.isra.0+0x189/0x2d0 [ 279.885037] ? tcf_block_setup+0x6b0/0x6b0 [ 279.885901] ? mutex_lock+0x7d/0xd0 [ 279.886669] ? __mutex_unlock_slowpath.constprop.0+0x2d0/0x2d0 [ 279.887844] ? ingress_init+0x1c0/0x1c0 [sch_ingress] [ 279.888846] tcf_block_get_ext+0x61c/0x1200 [ 279.889711] ingress_init+0x112/0x1c0 [sch_ingress] [ 279.890682] ? clsact_init+0x2b0/0x2b0 [sch_ingress] [ 279.891701] qdisc_create+0x401/0xea0 [ 279.892485] ? qdisc_tree_reduce_backlog+0x470/0x470 [ 279.893473] tc_modify_qdisc+0x6f7/0x16d0 [ 279.894344] ? tc_get_qdisc+0xac0/0xac0 [ 279.895213] ? mutex_lock+0x7d/0xd0 [ 279.896005] ? __mutex_lock_slowpath+0x10/0x10 [ 279.896910] rtnetlink_rcv_msg+0x5fe/0x9d0 [ 279.897770] ? rtnl_calcit.isra.0+0x2b0/0x2b0 [ 279.898672] ? __sys_sendmsg+0xb5/0x140 [ 279.899494] ? do_syscall_64+0x3d/0x90 [ 279.900302] ? entry_SYSCALL_64_after_hwframe+0x46/0xb0 [ 279.901337] ? kasan_save_stack+0x2e/0x40 [ 279.902177] ? kasan_save_stack+0x1e/0x40 [ 279.903058] ? kasan_set_track+0x21/0x30 [ 279.903913] ? kasan_save_free_info+0x2a/0x40 [ 279.904836] ? ____kasan_slab_free+0x11a/0x1b0 [ 279.905741] ? kmem_cache_free+0x179/0x400 [ 279.906599] netlink_rcv_skb+0x12c/0x360 [ 279.907450] ? rtnl_calcit.isra.0+0x2b0/0x2b0 [ 279.908360] ? netlink_ack+0x1550/0x1550 [ 279.909192] ? rhashtable_walk_peek+0x170/0x170 [ 279.910135] ? kmem_cache_alloc_node+0x1af/0x390 [ 279.911086] ? _copy_from_iter+0x3d6/0xc70 [ 279.912031] netlink_unicast+0x553/0x790 [ 279.912864] ? netlink_attachskb+0x6a0/0x6a0 [ 279.913763] ? netlink_recvmsg+0x416/0xb50 [ 279.914627] netlink_sendmsg+0x7a1/0xcb0 [ 279.915473] ? netlink_unicast+0x790/0x790 [ 279.916334] ? iovec_from_user.part.0+0x4d/0x220 [ 279.917293] ? netlink_unicast+0x790/0x790 [ 279.918159] sock_sendmsg+0xc5/0x190 [ 279.918938] ____sys_sendmsg+0x535/0x6b0 [ 279.919813] ? import_iovec+0x7/0x10 [ 279.920601] ? kernel_sendmsg+0x30/0x30 [ 279.921423] ? __copy_msghdr+0x3c0/0x3c0 [ 279.922254] ? import_iovec+0x7/0x10 [ 279.923041] ___sys_sendmsg+0xeb/0x170 [ 279.923854] ? copy_msghdr_from_user+0x110/0x110 [ 279.924797] ? ___sys_recvmsg+0xd9/0x130 [ 279.925630] ? __perf_event_task_sched_in+0x183/0x470 [ 279.926656] ? ___sys_sendmsg+0x170/0x170 [ 279.927529] ? ctx_sched_in+0x530/0x530 [ 279.928369] ? update_curr+0x283/0x4f0 [ 279.929185] ? perf_event_update_userpage+0x570/0x570 [ 279.930201] ? __fget_light+0x57/0x520 [ 279.931023] ? __switch_to+0x53d/0xe70 [ 27 ---truncated---
Quoted source text, attributed separately from HOL analysis.