# CVE-2026-80981: linux: In the Linux kernel, the following vulnerability has been resolved:  net/smc: fix use-after-free of the LLC qentry in...

CVE-2026-80981 is fixed in linux on 1 platform by DEBIAN-CVE-2026-80981 (version 7.2.6-1), released September 23, 2026. It is not reported as exploited. Patch Radar priority: Urgent.

- Web page: https://patchblox.com/security/cve/CVE-2026-80981
- Priority: Urgent
- CVSS: 9.8 (critical)
- EPSS: 0.0063
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 11, 2026

## Description

In the Linux kernel, the following vulnerability has been resolved:  net/smc: fix use-after-free of the LLC qentry in smc_llc_srv_add_link()  smc_llc_srv_add_link() keeps add_llc pointing into the queue entry:    add_llc = &qentry->msg.add_link;			smc_llc.c:1482   ...   smc_llc_save_add_link_info(link_new, add_llc);	smc_llc.c:1494   smc_llc_flow_qentry_del(&lgr->llc_flow_lcl);		smc_llc.c:1495   ...   u8 *llc_msg = smc_link_shared_v2_rxbuf(link) ? 	(u8 *)lgr->wr_rx_buf_v2 : (u8 *)add_llc;	smc_llc.c:1504   smc_llc_save_add_link_rkeys(link, link_new, llc_msg);	smc_llc.c:1506  smc_llc_flow_qentry_del() kfree()s the entry, so on a link without a shared v2 receive buffer the pointer handed to smc_llc_save_add_link_rkeys() is already freed. Before the Fixes: commit that branch always used lgr->wr_rx_buf_v2 and add_llc was not used after the free.  Reproduced on an unpatched tree over rxe, with KASAN, kasan_multi_shot and a link forced to max_recv_sge == 1: the entry is freed and read by the same call, and the freeing frame is smc_llc_srv_add_link() itself.    [    2.523161] BUG: KASAN: slab-use-after-free in smc_llc_save_add_link_rkeys+0x333/0x350   [    2.523499] Read of size 2 at addr ffff8880052194de by task kworker/0:1/11   [    2.523789]   [    2.523862] CPU: 0 UID: 0 PID: 11 Comm: kworker/0:1 Not tainted 7.2.0-rc5-p0-g2c9dd296545d #35 PREEMPT(lazy)   [    2.523865] Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014   [    2.523866] Workqueue: smc_hs_wq smc_listen_work   [    2.523869] Call Trace:   [    2.523870]  <TASK>   [    2.523871]  dump_stack_lvl+0x53/0x70   [    2.523872]  print_report+0xd0/0x630   [    2.523874]  ? __pfx__raw_spin_lock_irqsave+0x10/0x10   [    2.523876]  ? smc_llc_save_add_link_rkeys+0x333/0x350   [    2.523878]  kasan_report+0xce/0x100   [    2.523879]  ? smc_llc_save_add_link_rkeys+0x333/0x350   [    2.523881]  smc_llc_save_add_link_rkeys+0x333/0x350   [    2.523883]  ? smcr_buf_reg_lgr+0x2a4/0x660   [    2.523885]  smc_llc_srv_add_link+0xaa2/0x1e50   [    2.523888]  ? _printk+0xba/0xf0   [    2.523897]  ? __pfx_smc_llc_srv_add_link+0x10/0x10   [    2.523899]  ? down_write+0xb0/0x130   [    2.523903]  ? __pfx_down_write+0x10/0x10   [    2.523905]  smc_listen_work+0x489e/0x4d00   [    2.523907]  ? kmem_cache_free+0x1c6/0x3a0   [    2.523911]  ? __pfx_smc_listen_work+0x10/0x10   [    2.523913]  ? release_sock+0x148/0x1d0   [    2.523915]  ? smc_tcp_listen_work+0xb4f/0xfc0   [    2.523917]  ? _raw_spin_lock_irq+0x80/0xe0   [    2.523918]  ? __pfx__raw_spin_lock_irq+0x10/0x10   [    2.523920]  process_one_work+0x633/0x1030   [    2.523922]  ? assign_work+0x11d/0x370   [    2.523924]  worker_thread+0x45b/0xd10   [    2.523926]  ? __pfx_worker_thread+0x10/0x10   [    2.523928]  ? __pfx_worker_thread+0x10/0x10   [    2.523929]  kthread+0x2c6/0x3b0   [    2.523931]  ? recalc_sigpending+0x15c/0x1e0   [    2.523934]  ? __pfx_kthread+0x10/0x10   [    2.523935]  ret_from_fork+0x36e/0x5a0   [    2.523937]  ? __pfx_ret_from_fork+0x10/0x10   [    2.523938]  ? __switch_to+0x572/0xdd0   [    2.523943]  ? __pfx_kthread+0x10/0x10   [    2.523944]  ret_from_fork_asm+0x1a/0x30   [    2.523947]  </TASK>   [    2.523948]   [    2.531253] Allocated by task 48:   [    2.531399]  kasan_save_stack+0x33/0x60   [    2.531570]  kasan_save_track+0x14/0x30   [    2.531737]  __kasan_kmalloc+0x8f/0xa0   [    2.531905]  __kmalloc_cache_noprof+0x158/0x370   [    2.532100]  smc_llc_enqueue+0x72/0x560   [    2.532268]  smc_wr_rx_tasklet_fn+0x474/0xa80   [    2.532491]  tasklet_action_common+0x20f/0x8a0   [    2.532714]  handle_softirqs+0x18e/0x590   [    2.532886]  do_softirq+0x3b/0x60   [    2.533036]  __local_bh_enable_ip+0x61/0x70   [    2.533221]  __alloc_skb+0x732/0x890   [    2.533384]  rxe_init_packet+0x16b/0x4f0   [    2.533567]  prepare_ack_packet+0xb8/0x830   [    2.533760]  rxe_receiver+0x495/0x96e0   [    2.533933]  do_work+0x144/0x470   [    2 ---truncated---

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 14 | 7.2.6-1 | [DEBIAN-CVE-2026-80981](https://patchblox.com/security/data/fix/linux/debian-cve-2026-80981.md) | Sep 23, 2026 |

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Data as of 2026-11-09T07:25:28Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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