CVE-2026-80986 (GCVE-0-2026-80986)
Vulnerability from cvelistv5
Published
2026-09-11 19:42
Modified
2026-10-19 08:46
Severity ?
9.8 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: net/smc: bound the peer rkey counts in SMC-Rv2 LLC messages On a link whose device has max_recv_sge == 1 there is no shared v2 receive buffer, and smc_llc_save_add_link_rkeys() takes the v2 extension from 44 bytes past the start of the queue entry's inline message: ext = (struct smc_llc_msg_add_link_v2_ext *)(llc_msg + SMC_WR_TX_SIZE); The entry is a 72-byte allocation and the extension starts at offset 68, so ext->num_rkeys at offset 94 is already past it. This happens on every SMC-Rv2 link addition, whatever the peer sends: [ 2.490065] BUG: KASAN: slab-out-of-bounds in smc_llc_save_add_link_rkeys+0x333/0x350 [ 2.490431] Read of size 2 at addr ffff8880056406de by task smctest/106 [ 2.490709] [ 2.490792] CPU: 0 UID: 0 PID: 106 Comm: smctest Not tainted 7.2.0-rc5-p1-g77a5d9d9c99f #32 PREEMPT(lazy) [ 2.490795] 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 [ 2.490798] Call Trace: [ 2.490803] <TASK> [ 2.490805] dump_stack_lvl+0x53/0x70 [ 2.490810] print_report+0xd0/0x630 [ 2.490828] ? __pfx__raw_spin_lock_irqsave+0x10/0x10 [ 2.490832] ? smc_llc_save_add_link_rkeys+0x333/0x350 [ 2.490834] kasan_report+0xce/0x100 [ 2.490836] ? smc_llc_save_add_link_rkeys+0x333/0x350 [ 2.490837] smc_llc_save_add_link_rkeys+0x333/0x350 [ 2.490839] ? smcr_buf_map_lgr+0x1bf/0x2b0 [ 2.490844] smc_llc_cli_add_link+0xca7/0x1e80 [ 2.490848] ? smc_llc_wait+0x355/0x810 [ 2.490850] ? __pfx_smc_llc_wait+0x10/0x10 [ 2.490851] ? __pfx_smc_llc_cli_add_link+0x10/0x10 [ 2.490853] ? __pfx_autoremove_wake_function+0x10/0x10 [ 2.490863] __smc_connect+0x3f5c/0x4980 [ 2.490873] ? __pfx_kernel_connect+0x10/0x10 [ 2.490888] ? __pfx___smc_connect+0x10/0x10 [ 2.490891] ? release_sock+0x148/0x1d0 [ 2.490894] smc_connect+0x42c/0x580 [ 2.490896] __sys_connect+0xfc/0x130 [ 2.490898] ? __pfx___sys_connect+0x10/0x10 [ 2.490900] ? handle_mm_fault+0x1a1/0x430 [ 2.490908] __x64_sys_connect+0x6d/0xb0 [ 2.490909] ? fpregs_assert_state_consistent+0x56/0xe0 [ 2.490917] do_syscall_64+0xf9/0x540 [ 2.490921] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 2.490924] RIP: 0033:0x421bb4 [ 2.490927] Code: ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 80 3d ad 34 09 00 00 74 13 b8 2a 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 4c c3 0f 1f 00 55 48 89 e5 48 83 ec 10 89 55 [ 2.490929] RSP: 002b:00007ffd473b01a8 EFLAGS: 00000202 ORIG_RAX: 000000000000002a [ 2.490935] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000421bb4 [ 2.490936] RDX: 0000000000000010 RSI: 00007ffd473b01d0 RDI: 0000000000000003 [ 2.490937] RBP: 0000000000003930 R08: 0000000000000004 R09: 0000000000000000 [ 2.490938] R10: 00007ffd473b0f98 R11: 0000000000000202 R12: 0000000000000006 [ 2.490939] R13: 00007ffd473b0f87 R14: 0000000000000003 R15: 00007ffd473b0f90 [ 2.490940] </TASK> [ 2.490941] [ 2.499545] Allocated by task 44: [ 2.499693] kasan_save_stack+0x33/0x60 [ 2.499860] kasan_save_track+0x14/0x30 [ 2.500026] __kasan_kmalloc+0x8f/0xa0 [ 2.500190] __kmalloc_cache_noprof+0x158/0x370 [ 2.500393] smc_llc_enqueue+0x72/0x560 [ 2.500559] smc_wr_rx_tasklet_fn+0x474/0xa80 [ 2.500747] tasklet_action_common+0x20f/0x8a0 [ 2.500945] handle_softirqs+0x18e/0x590 [ 2.501115] do_softirq+0x3b/0x60 [ 2.501266] __local_bh_enable_ip+0x61/0x70 [ 2.501446] __alloc_skb+0x732/0x890 [ 2.501604] rxe_init_packet+0x16b/0x4f0 [ 2.501783] prepare_ack_packet+0xb8/0x830 [ 2.501962] rxe_receiver+0x495/0x96e0 [ 2.502125] do_work+0x144/0x470 [ 2.502269] process_one_work+0x633/0x1030 [ 2.502450] worker_thread+0x45b/0xd10 [ 2.50261 ---truncated---
References
Impacted products
Vendor Product Version
Linux Linux Version: 27ef6a9981fe74191849966a6d5e0400a4008ab8
Version: 27ef6a9981fe74191849966a6d5e0400a4008ab8
Version: 27ef6a9981fe74191849966a6d5e0400a4008ab8
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/smc/smc_llc.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "486c699a8cde82c1d9b4f443eeab4ddf86358cb0",
              "status": "affected",
              "version": "27ef6a9981fe74191849966a6d5e0400a4008ab8",
              "versionType": "git"
            },
            {
              "lessThan": "5e5d9e6df677d30a2203d257b5fd8b99814fa607",
              "status": "affected",
              "version": "27ef6a9981fe74191849966a6d5e0400a4008ab8",
              "versionType": "git"
            },
            {
              "lessThan": "2d1e7c5aaa3326e95e2058457f172ca99a9a4577",
              "status": "affected",
              "version": "27ef6a9981fe74191849966a6d5e0400a4008ab8",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/smc/smc_llc.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.14"
            },
            {
              "lessThan": "6.14",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.50",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.50",
                  "versionStartIncluding": "6.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.4",
                  "versionStartIncluding": "6.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3",
                  "versionStartIncluding": "6.14",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/smc: bound the peer rkey counts in SMC-Rv2 LLC messages\n\nOn a link whose device has max_recv_sge == 1 there is no shared v2 receive\nbuffer, and smc_llc_save_add_link_rkeys() takes the v2 extension from 44\nbytes past the start of the queue entry\u0027s inline message:\n\n  ext = (struct smc_llc_msg_add_link_v2_ext *)(llc_msg + SMC_WR_TX_SIZE);\n\nThe entry is a 72-byte allocation and the extension starts at offset 68, so\next-\u003enum_rkeys at offset 94 is already past it. This happens on every\nSMC-Rv2 link addition, whatever the peer sends:\n\n  [    2.490065] BUG: KASAN: slab-out-of-bounds in smc_llc_save_add_link_rkeys+0x333/0x350\n  [    2.490431] Read of size 2 at addr ffff8880056406de by task smctest/106\n  [    2.490709]\n  [    2.490792] CPU: 0 UID: 0 PID: 106 Comm: smctest Not tainted 7.2.0-rc5-p1-g77a5d9d9c99f #32 PREEMPT(lazy)\n  [    2.490795] 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  [    2.490798] Call Trace:\n  [    2.490803]  \u003cTASK\u003e\n  [    2.490805]  dump_stack_lvl+0x53/0x70\n  [    2.490810]  print_report+0xd0/0x630\n  [    2.490828]  ? __pfx__raw_spin_lock_irqsave+0x10/0x10\n  [    2.490832]  ? smc_llc_save_add_link_rkeys+0x333/0x350\n  [    2.490834]  kasan_report+0xce/0x100\n  [    2.490836]  ? smc_llc_save_add_link_rkeys+0x333/0x350\n  [    2.490837]  smc_llc_save_add_link_rkeys+0x333/0x350\n  [    2.490839]  ? smcr_buf_map_lgr+0x1bf/0x2b0\n  [    2.490844]  smc_llc_cli_add_link+0xca7/0x1e80\n  [    2.490848]  ? smc_llc_wait+0x355/0x810\n  [    2.490850]  ? __pfx_smc_llc_wait+0x10/0x10\n  [    2.490851]  ? __pfx_smc_llc_cli_add_link+0x10/0x10\n  [    2.490853]  ? __pfx_autoremove_wake_function+0x10/0x10\n  [    2.490863]  __smc_connect+0x3f5c/0x4980\n  [    2.490873]  ? __pfx_kernel_connect+0x10/0x10\n  [    2.490888]  ? __pfx___smc_connect+0x10/0x10\n  [    2.490891]  ? release_sock+0x148/0x1d0\n  [    2.490894]  smc_connect+0x42c/0x580\n  [    2.490896]  __sys_connect+0xfc/0x130\n  [    2.490898]  ? __pfx___sys_connect+0x10/0x10\n  [    2.490900]  ? handle_mm_fault+0x1a1/0x430\n  [    2.490908]  __x64_sys_connect+0x6d/0xb0\n  [    2.490909]  ? fpregs_assert_state_consistent+0x56/0xe0\n  [    2.490917]  do_syscall_64+0xf9/0x540\n  [    2.490921]  entry_SYSCALL_64_after_hwframe+0x77/0x7f\n  [    2.490924] RIP: 0033:0x421bb4\n  [    2.490927] Code: ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 80 3d ad 34 09 00 00 74 13 b8 2a 00 00 00 0f 05 \u003c48\u003e 3d 00 f0 ff ff 77 4c c3 0f 1f 00 55 48 89 e5 48 83 ec 10 89 55\n  [    2.490929] RSP: 002b:00007ffd473b01a8 EFLAGS: 00000202 ORIG_RAX: 000000000000002a\n  [    2.490935] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000421bb4\n  [    2.490936] RDX: 0000000000000010 RSI: 00007ffd473b01d0 RDI: 0000000000000003\n  [    2.490937] RBP: 0000000000003930 R08: 0000000000000004 R09: 0000000000000000\n  [    2.490938] R10: 00007ffd473b0f98 R11: 0000000000000202 R12: 0000000000000006\n  [    2.490939] R13: 00007ffd473b0f87 R14: 0000000000000003 R15: 00007ffd473b0f90\n  [    2.490940]  \u003c/TASK\u003e\n  [    2.490941]\n  [    2.499545] Allocated by task 44:\n  [    2.499693]  kasan_save_stack+0x33/0x60\n  [    2.499860]  kasan_save_track+0x14/0x30\n  [    2.500026]  __kasan_kmalloc+0x8f/0xa0\n  [    2.500190]  __kmalloc_cache_noprof+0x158/0x370\n  [    2.500393]  smc_llc_enqueue+0x72/0x560\n  [    2.500559]  smc_wr_rx_tasklet_fn+0x474/0xa80\n  [    2.500747]  tasklet_action_common+0x20f/0x8a0\n  [    2.500945]  handle_softirqs+0x18e/0x590\n  [    2.501115]  do_softirq+0x3b/0x60\n  [    2.501266]  __local_bh_enable_ip+0x61/0x70\n  [    2.501446]  __alloc_skb+0x732/0x890\n  [    2.501604]  rxe_init_packet+0x16b/0x4f0\n  [    2.501783]  prepare_ack_packet+0xb8/0x830\n  [    2.501962]  rxe_receiver+0x495/0x96e0\n  [    2.502125]  do_work+0x144/0x470\n  [    2.502269]  process_one_work+0x633/0x1030\n  [    2.502450]  worker_thread+0x45b/0xd10\n  [    2.50261\n---truncated---"
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 9.8,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - The OOB is reached from SMC-Rv2 LLC ADD_LINK and DELETE_RKEY handling on the RDMA RX path (smc_wr_rx_tasklet_fn\u2192smc_llc_rx_handler\u2192smc_llc_enqueue). CLC is plain TCP and SMC-Rv2/RoCEv2 LLC is IP-routable (UDP/4791), so a remote peer that can reach an AF_SMC listener drives the path.\nAC:L - On SMC-Rv2 links with max_recv_sge==1 (the supported device class this bug exists for), every ADD_LINK reads past the 72-byte qentry regardless of peer contents, and a DELETE_RKEY_V2 with num_rkeys=255 walks up to 255 rkeys off the object; no race or attacker-uncontrollable layout is required.\nPR:N - SMC authenticates nothing. smc_create()/smc_listen() enforce no capabilities, and smc_listen_work() runs the CLC/LLC handshake after TCP accept before accept() returns to userspace, so an unauthenticated network peer needs only reachability to the listener.\nUI:N - The listen worker is queued automatically from smc_tcp_listen_work() for inbound connections, and DELETE_RKEY is processed in the LLC event worker from RDMA completions; no local user action such as mounting a filesystem or opening a file is required.\nS:U - The slab out-of-bounds read and the resulting writes into the link-group rtoken table stay inside the host kernel (kmalloc qentry, lgr-\u003ertokens) and do not cross a VM, IOMMU, or sandbox boundary.\nC:H - smc_llc_save_add_link_rkeys() reads ext-\u003enum_rkeys 22 bytes past the 72-byte qentry and then walks up to 255 16-byte rt[] entries of adjacent heap; smc_llc_rmt_delete_rkey() similarly out-of-bounds-reads rkey[9..254]. Per kernel CNA guidance a large heap out-of-bounds read is High.\nI:H - Those out-of-bounds bytes are passed to smc_rtoken_set() (writes rkey/dma_addr into lgr-\u003ertokens) and smc_rtoken_delete() (clears matching rtokens). Adjacent kmalloc-96 spray lets a peer influence the written values, corrupting RDMA targeting used by ib_post_send.\nA:H - KASAN reports slab-out-of-bounds in smc_llc_save_add_link_rkeys on every affected ADD_LINK; a multi-kilobyte walk off a 72-byte object can oops when it hits an unmapped page, and a remote peer can repeat the handshake or DELETE_RKEY at will."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T08:46:10.570Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/486c699a8cde82c1d9b4f443eeab4ddf86358cb0"
        },
        {
          "url": "https://git.kernel.org/stable/c/5e5d9e6df677d30a2203d257b5fd8b99814fa607"
        },
        {
          "url": "https://git.kernel.org/stable/c/2d1e7c5aaa3326e95e2058457f172ca99a9a4577"
        }
      ],
      "title": "net/smc: bound the peer rkey counts in SMC-Rv2 LLC messages",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-80986",
    "datePublished": "2026-09-11T19:42:44.904Z",
    "dateReserved": "2026-08-26T14:34:25.811Z",
    "dateUpdated": "2026-10-19T08:46:10.570Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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