{"id":"CVE-2026-80981","title":"net/smc: fix use-after-free of the LLC qentry in smc_llc_srv_add_link()","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/smc: fix use-after-free of the LLC qentry in smc_llc_srv_add_link()\n\nsmc_llc_srv_add_link() keeps add_llc pointing into the queue entry:\n\n  add_llc = &qentry->msg.a…","severity":"critical","cvss":9.8,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cvssSource":"cna","cwe":["CWE-825"],"vendor":"Linux","product":"Linux","affected":["Linux >= 27ef6a9981fe74191849966a6d5e0400a4008ab8 < c52a998a223e7e84333306996edec096178d1e95","Linux >= 27ef6a9981fe74191849966a6d5e0400a4008ab8 < adef84cc85d449ac28d2b4b4c49cf19619c56e27","Linux >= 27ef6a9981fe74191849966a6d5e0400a4008ab8 < a42a459ef0e54cb0c4b3e43e21cb0e658e664f64","Linux 6.14"],"published":"2026-09-11","updated":"2026-10-19","sourceUpdated":"2026-10-19T08:46:05.740Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-80981","references":[{"url":"https://git.kernel.org/stable/c/c52a998a223e7e84333306996edec096178d1e95"},{"url":"https://git.kernel.org/stable/c/adef84cc85d449ac28d2b4b4c49cf19619c56e27"},{"url":"https://git.kernel.org/stable/c/a42a459ef0e54cb0c4b3e43e21cb0e658e664f64"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-80981.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-80981"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2532104"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-80981"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-80981"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-80981.mbox"}],"tags":["cve.org","csaf","vex","red-hat","score-dispute"],"epss":0.00631,"epssPercentile":0.50048,"scores":{"cna":9.8,"vendor":7},"ingestedAt":"2026-09-14T15:23:07.476Z","slug":"CVE-2026-80981","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nnet/smc: fix use-after-free of the LLC qentry in smc_llc_srv_add_link()\n\nsmc_llc_srv_add_link() keeps add_llc pointing into the queue entry:\n\n  add_llc = &qentry->msg.add_link;\t\t\tsmc_llc.c:1482\n  ...\n  smc_llc_save_add_link_info(link_new, add_llc);\tsmc_llc.c:1494\n  smc_llc_flow_qentry_del(&lgr->llc_flow_lcl);\t\tsmc_llc.c:1495\n  ...\n  u8 *llc_msg = smc_link_shared_v2_rxbuf(link) ?\n\t(u8 *)lgr->wr_rx_buf_v2 : (u8 *)add_llc;\tsmc_llc.c:1504\n  smc_llc_save_add_link_rkeys(link, link_new, llc_msg);\tsmc_llc.c:1506\n\nsmc_llc_flow_qentry_del() kfree()s the entry, so on a link without a shared\nv2 receive buffer the pointer handed to smc_llc_save_add_link_rkeys() is\nalready freed. Before the Fixes: commit that branch always used\nlgr->wr_rx_buf_v2 and add_llc was not used after the free.\n\nReproduced on an unpatched tree over rxe, with KASAN, kasan_multi_shot\nand a link forced to max_recv_sge == 1: the entry is freed and read by\nthe same call, and the freeing frame is smc_llc_srv_add_link() itself.\n\n  [    2.523161] BUG: KASAN: slab-use-after-free in smc_llc_save_add_link_rkeys+0x333/0x350\n  [    2.523499] Read of size 2 at addr ffff8880052194de by task kworker/0:1/11\n  [    2.523789]\n  [    2.523862] CPU: 0 UID: 0 PID: 11 Comm: kworker/0:1 Not tainted 7.2.0-rc5-p0-g2c9dd296545d #35 PREEMPT(lazy)\n  [    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\n  [    2.523866] Workqueue: smc_hs_wq smc_listen_work\n  [    2.523869] Call Trace:\n  [    2.523870]  <TASK>\n  [    2.523871]  dump_stack_lvl+0x53/0x70\n  [    2.523872]  print_report+0xd0/0x630\n  [    2.523874]  ? __pfx__raw_spin_lock_irqsave+0x10/0x10\n  [    2.523876]  ? smc_llc_save_add_link_rkeys+0x333/0x350\n  [    2.523878]  kasan_report+0xce/0x100\n  [    2.523879]  ? smc_llc_save_add_link_rkeys+0x333/0x350\n  [    2.523881]  smc_llc_save_add_link_rkeys+0x333/0x350\n  [    2.523883]  ? smcr_buf_reg_lgr+0x2a4/0x660\n  [    2.523885]  smc_llc_srv_add_link+0xaa2/0x1e50\n  [    2.523888]  ? _printk+0xba/0xf0\n  [    2.523897]  ? __pfx_smc_llc_srv_add_link+0x10/0x10\n  [    2.523899]  ? down_write+0xb0/0x130\n  [    2.523903]  ? __pfx_down_write+0x10/0x10\n  [    2.523905]  smc_listen_work+0x489e/0x4d00\n  [    2.523907]  ? kmem_cache_free+0x1c6/0x3a0\n  [    2.523911]  ? __pfx_smc_listen_work+0x10/0x10\n  [    2.523913]  ? release_sock+0x148/0x1d0\n  [    2.523915]  ? smc_tcp_listen_work+0xb4f/0xfc0\n  [    2.523917]  ? _raw_spin_lock_irq+0x80/0xe0\n  [    2.523918]  ? __pfx__raw_spin_lock_irq+0x10/0x10\n  [    2.523920]  process_one_work+0x633/0x1030\n  [    2.523922]  ? assign_work+0x11d/0x370\n  [    2.523924]  worker_thread+0x45b/0xd10\n  [    2.523926]  ? __pfx_worker_thread+0x10/0x10\n  [    2.523928]  ? __pfx_worker_thread+0x10/0x10\n  [    2.523929]  kthread+0x2c6/0x3b0\n  [    2.523931]  ? recalc_sigpending+0x15c/0x1e0\n  [    2.523934]  ? __pfx_kthread+0x10/0x10\n  [    2.523935]  ret_from_fork+0x36e/0x5a0\n  [    2.523937]  ? __pfx_ret_from_fork+0x10/0x10\n  [    2.523938]  ? __switch_to+0x572/0xdd0\n  [    2.523943]  ? __pfx_kthread+0x10/0x10\n  [    2.523944]  ret_from_fork_asm+0x1a/0x30\n  [    2.523947]  </TASK>\n  [    2.523948]\n  [    2.531253] Allocated by task 48:\n  [    2.531399]  kasan_save_stack+0x33/0x60\n  [    2.531570]  kasan_save_track+0x14/0x30\n  [    2.531737]  __kasan_kmalloc+0x8f/0xa0\n  [    2.531905]  __kmalloc_cache_noprof+0x158/0x370\n  [    2.532100]  smc_llc_enqueue+0x72/0x560\n  [    2.532268]  smc_wr_rx_tasklet_fn+0x474/0xa80\n  [    2.532491]  tasklet_action_common+0x20f/0x8a0\n  [    2.532714]  handle_softirqs+0x18e/0x590\n  [    2.532886]  do_softirq+0x3b/0x60\n  [    2.533036]  __local_bh_enable_ip+0x61/0x70\n  [    2.533221]  __alloc_skb+0x732/0x890\n  [    2.533384]  rxe_init_packet+0x16b/0x4f0\n  [    2.533567]  prepare_ack_packet+0xb8/0x830\n  [    2.533760]  rxe_receiver+0x495/0x96e0\n  [    2.533933]  do_work+0x144/0x470\n  [    2\n---truncated---\n\n## Affected\n\n- `Linux >= 27ef6a9981fe74191849966a6d5e0400a4008ab8 < c52a998a223e7e84333306996edec096178d1e95`\n- `Linux >= 27ef6a9981fe74191849966a6d5e0400a4008ab8 < adef84cc85d449ac28d2b4b4c49cf19619c56e27`\n- `Linux >= 27ef6a9981fe74191849966a6d5e0400a4008ab8 < a42a459ef0e54cb0c4b3e43e21cb0e658e664f64`\n- `Linux 6.14`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · updated 2026-09-14 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-80981.json)","depth":"midnight","depthScore":54,"depthScoreParts":{"impact":53.9,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[{"seq":224793,"id":"CVE-2026-80981","ts":1792401546039,"field":"cvss","old":"7","new":"9.8"},{"seq":224792,"id":"CVE-2026-80981","ts":1792401546039,"field":"severity","old":"high","new":"critical"},{"seq":204176,"id":"CVE-2026-80981","ts":1789490236203,"field":"cvss","old":"5.2","new":"7"},{"seq":204175,"id":"CVE-2026-80981","ts":1789490236203,"field":"severity","old":"medium","new":"high"},{"seq":202943,"id":"CVE-2026-80981","ts":1789403733048,"field":"cvss","old":"9.8","new":"5.2"},{"seq":202942,"id":"CVE-2026-80981","ts":1789403733048,"field":"severity","old":"critical","new":"medium"},{"seq":183592,"id":"CVE-2026-80981","ts":1789356676019,"field":"cvss","old":"9.8","new":"5.2"},{"seq":183591,"id":"CVE-2026-80981","ts":1789356676019,"field":"severity","old":"critical","new":"medium"},{"seq":153166,"id":"CVE-2026-80981","ts":1789285349374,"field":"cvss","old":null,"new":"9.8"},{"seq":153165,"id":"CVE-2026-80981","ts":1789285349374,"field":"severity","old":"none","new":"critical"},{"seq":147740,"id":"CVE-2026-80981","ts":1789270212107,"field":"cvss","old":null,"new":"5.2"},{"seq":147739,"id":"CVE-2026-80981","ts":1789270212107,"field":"severity","old":"none","new":"medium"},{"seq":109494,"id":"CVE-2026-80981","ts":1789183732130,"field":"cvss","old":null,"new":"5.2"},{"seq":109493,"id":"CVE-2026-80981","ts":1789183732130,"field":"severity","old":"none","new":"medium"}]}