CVE-2026-90294

Status: ReceivedHigh (7.5)—

In the Linux kernel, the following vulnerability has been resolved:

IB/isert: delay the final Login Response until the session is registered

isert_put_login_tx() puts the final Login Response on the wire before __transport_register_session(), which iscsi_post_login_handler() reaches only after iscsi_target_do_login() returns. An initiator that issues a SCSI command as soon as it sees that response can have it executed against an se_session whose se_tpg is still NULL, and the ib-comp-wq worker oopses on the NULL dereference.

Delay the final Login Response instead. isert_get_rx_pdu() runs from iscsi_target_rx_thread() after conn->rx_login_comp, completed by iscsi_post_login_handler() after __transport_register_session(); iscsi-TCP and cxgbit already take PDUs from that thread, isert alone does not.

Read full descriptionShow less

The buffers are still posted first, so the initiator's first command does not meet an empty receive queue and nothing depends on RNR flow control, and the header and payload live in isert_conn, not in the struct iscsi_login that iscsi_target_nego_release() frees first.

Over rxe, 400 login cycles per run, the oops appeared in 10 of 20 unpatched runs and in none of 20 runs with this patch. An initiator that never waits is handled by the next patch.

Not tested: iWARP, discovery sessions over iSER, and real HCAs.

Technical details traces, logs and code from the original report

 Oops: general protection fault, probably for non-canonical address 0xdffffc000000000f: 0000 [#1] SMP KASAN NOPTI
 KASAN: null-ptr-deref in range [0x0000000000000078-0x000000000000007f]
 CPU: 0 UID: 0 PID: 178 Comm: kworker/0:1H Not tainted 7.2.0-rc5-V2CTL-gf5098b6bae76 #10 PREEMPT(lazy)
 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
 Workqueue: ib-comp-wq ib_cq_poll_work
 RIP: 0010:target_submit+0xbe/0x390
 Code: fa 48 c1 ea 03 80 3c 02 00 0f 85 89 02 00 00 48 b8 00 00 00 00 00 fc ff df 4d 8b 64 24 18 49 8d 7c 24 78 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 5a 02 00 00 48 8d 7b 78 4d 8b 6c 24 78 48 b8 00
 RSP: 0018:ffff8881058cfa78 EFLAGS: 00010206
 RAX: dffffc0000000000 RBX: ffff88810c78c6f0 RCX: ffffffff964bb363
 RDX: 000000000000000f RSI: 00000000fffffe00 RDI: 0000000000000078
 RBP: 1ffff11020b19f52 R08: 0000000000000001 R09: ffffed1020b19f52
 R10: 0000000000000003 R11: ffff88810596c000 R12: 0000000000000000
 R13: ffff88810c61b000 R14: ffff88810c6a3400 R15: ffff88810c61b044
 FS:  0000000000000000(0000) GS:ffff8881822b2000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 00007f1f1b83c000 CR3: 000000006fe72001 CR4: 0000000000770ef0
 PKRU: 55555554
 Call Trace:
  <TASK>
  ? __pfx__raw_spin_lock_bh+0x10/0x10
  ? __pfx_target_submit+0x10/0x10
  ? mutex_lock+0x81/0xe0
  ? __pfx_mutex_lock+0x10/0x10
  ? iscsit_execute_cmd+0x650/0x850
  iscsit_sequence_cmd+0x186/0x3d0
  iscsit_process_scsi_cmd+0x87/0x300
  isert_recv_done+0x1002/0x2390
  ? __pfx_isert_recv_done+0x10/0x10
  ? rxe_poll_cq+0x253/0x3d0
  ? finish_task_switch.isra.0+0x1dc/0xa70
  __ib_process_cq+0xe1/0x390
  ib_cq_poll_work+0x46/0x150
  process_one_work+0x633/0x1030
  ? assign_work+0x11d/0x370
  worker_thread+0x45b/0xd10
  ? __pfx_worker_thread+0x10/0x10
  ? __pfx_worker_thread+0x10/0x10
  kthread+0x2c6/0x3b0
  ? recalc_sigpending+0x15c/0x1e0
  ? __pfx_kthread+0x10/0x10
  ret_from_fork+0x36e/0x5a0
  ? __pfx_ret_from_fork+0x10/0x10
  ? __switch_to+0x572/0xdd0
  ? __pfx_kthread+0x10/0x10
  ret_from_fork_asm+0x1a/0x30
  </TASK>
 Modules linked in:
 ---[ end trace 0000000000000000 ]---

CVSS

Version: 3.1
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Base score: 7.5

Exploitation probability (EPSS)

Probability of exploitation in the next 30 days: 0.72%
Percentile among all scored CVEs: 52
Score date: 10/5/2026

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

🎯 ATT&CK techniques

How this vulnerability is exploited and what the attacker gains, in MITRE ATT&CK terms.

ExploitationT1190 Exploit Public-Facing Applicationinitial access75 %
Primary impactT1499.004 Application or System Exploitationimpact85 %
Secondary impactT1529 System Shutdown/Rebootimpact60 %

Vulnerabilidad de negociación de sesión en kernel Linux (iSER/iSCSI) explotable remotamente sin autenticación. Causa NULL dereference en worker thread al procesar comandos SCSI antes de registrar sesión, resultando en crash del kernel (DoS). Vector AV:N/AC:L/PR:N/UI:N, impacto A:H confirma disponibi

Inferred by our analysis agent from the official description, CVSS vector and CWE, and checked by a supervisor. May contain errors.

🛡️ ATT&CK mitigations that cover these techniques

Filter Network Traffic Vulnerability Scanning Privileged Account Management Network Segmentation Limit Access to Resource Over Network Application Isolation and Sandboxing

Affected technologies (1)

⚠ AI-inferred from the description — NVD hasn't analyzed this CVE yet, these aren't verified CPEs.

Linux — Linux Kernel^AI

References

Raw JSON (NVD)

Show

{
  "id": "CVE-2026-90294",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.5,
          "attackVector": "NETWORK",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 3.6,
        "exploitabilityScore": 3.9
      }
    ]
  },
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
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          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "b8d26b3be8b33682cf163274ed07479a70554633",
              "lessThan": "e148dbac43308d9e4313070bfc5b355d03134809",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "b8d26b3be8b33682cf163274ed07479a70554633",
              "lessThan": "a18fb8d540b3e631cb7e50e55f3c462c05b3a114",
              "versionType": "git"
            },
            {
              "status": "affected",
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              "lessThan": "0d2efc355982064855f24f73f9fbb6c65ca4a5c7",
              "versionType": "git"
            },
            {
              "status": "affected",
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              "versionType": "git"
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              "lessThan": "11694889c4bab47047a60690ceb70d7551ed5b2e",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "b8d26b3be8b33682cf163274ed07479a70554633",
              "lessThan": "a6c19af05c170f267eca1d01c3c72c84ba7860ae",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "b8d26b3be8b33682cf163274ed07479a70554633",
              "lessThan": "4397ea31e3b0d017c2b9b876b326df0b3eb845bf",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "b8d26b3be8b33682cf163274ed07479a70554633",
              "lessThan": "464f5afa92d071a226f88424803b0fcf88093ede",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "drivers/infiniband/ulp/isert/ib_isert.c",
            "drivers/infiniband/ulp/isert/ib_isert.h"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "3.10"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "3.10",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "5.10.270",
              "versionType": "semver",
              "lessThanOrEqual": "5.10.*"
            },
            {
              "status": "unaffected",
              "version": "5.15.221",
              "versionType": "semver",
              "lessThanOrEqual": "5.15.*"
            },
            {
              "status": "unaffected",
              "version": "6.1.188",
              "versionType": "semver",
              "lessThanOrEqual": "6.1.*"
            },
            {
              "status": "unaffected",
              "version": "6.6.157",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "status": "unaffected",
              "version": "6.12.110",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.52",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "7.2.6",
              "versionType": "semver",
              "lessThanOrEqual": "7.2.*"
            },
            {
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "drivers/infiniband/ulp/isert/ib_isert.c",
            "drivers/infiniband/ulp/isert/ib_isert.h"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-09-17T17:17:26.693",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/0d2efc355982064855f24f73f9fbb6c65ca4a5c7",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/11694889c4bab47047a60690ceb70d7551ed5b2e",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/4397ea31e3b0d017c2b9b876b326df0b3eb845bf",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/464f5afa92d071a226f88424803b0fcf88093ede",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/a18fb8d540b3e631cb7e50e55f3c462c05b3a114",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/a6c19af05c170f267eca1d01c3c72c84ba7860ae",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/e148dbac43308d9e4313070bfc5b355d03134809",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/f84e9adf4d9f4c0c79ef4a7d9e0c5c08b1337033",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nIB/isert: delay the final Login Response until the session is registered\n\nisert_put_login_tx() puts the final Login Response on the wire before\n__transport_register_session(), which iscsi_post_login_handler() reaches\nonly after iscsi_target_do_login() returns.  An initiator that issues a\nSCSI command as soon as it sees that response can have it executed against\nan se_session whose se_tpg is still NULL, and the ib-comp-wq worker oopses\non the NULL dereference.\n\n Oops: general protection fault, probably for non-canonical address 0xdffffc000000000f: 0000 [#1] SMP KASAN NOPTI\n KASAN: null-ptr-deref in range [0x0000000000000078-0x000000000000007f]\n CPU: 0 UID: 0 PID: 178 Comm: kworker/0:1H Not tainted 7.2.0-rc5-V2CTL-gf5098b6bae76 #10 PREEMPT(lazy)\n 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 Workqueue: ib-comp-wq ib_cq_poll_work\n RIP: 0010:target_submit+0xbe/0x390\n Code: fa 48 c1 ea 03 80 3c 02 00 0f 85 89 02 00 00 48 b8 00 00 00 00 00 fc ff df 4d 8b 64 24 18 49 8d 7c 24 78 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 5a 02 00 00 48 8d 7b 78 4d 8b 6c 24 78 48 b8 00\n RSP: 0018:ffff8881058cfa78 EFLAGS: 00010206\n RAX: dffffc0000000000 RBX: ffff88810c78c6f0 RCX: ffffffff964bb363\n RDX: 000000000000000f RSI: 00000000fffffe00 RDI: 0000000000000078\n RBP: 1ffff11020b19f52 R08: 0000000000000001 R09: ffffed1020b19f52\n R10: 0000000000000003 R11: ffff88810596c000 R12: 0000000000000000\n R13: ffff88810c61b000 R14: ffff88810c6a3400 R15: ffff88810c61b044\n FS:  0000000000000000(0000) GS:ffff8881822b2000(0000) knlGS:0000000000000000\n CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n CR2: 00007f1f1b83c000 CR3: 000000006fe72001 CR4: 0000000000770ef0\n PKRU: 55555554\n Call Trace:\n  <TASK>\n  ? __pfx__raw_spin_lock_bh+0x10/0x10\n  ? __pfx_target_submit+0x10/0x10\n  ? mutex_lock+0x81/0xe0\n  ? __pfx_mutex_lock+0x10/0x10\n  ? iscsit_execute_cmd+0x650/0x850\n  iscsit_sequence_cmd+0x186/0x3d0\n  iscsit_process_scsi_cmd+0x87/0x300\n  isert_recv_done+0x1002/0x2390\n  ? __pfx_isert_recv_done+0x10/0x10\n  ? rxe_poll_cq+0x253/0x3d0\n  ? finish_task_switch.isra.0+0x1dc/0xa70\n  __ib_process_cq+0xe1/0x390\n  ib_cq_poll_work+0x46/0x150\n  process_one_work+0x633/0x1030\n  ? assign_work+0x11d/0x370\n  worker_thread+0x45b/0xd10\n  ? __pfx_worker_thread+0x10/0x10\n  ? __pfx_worker_thread+0x10/0x10\n  kthread+0x2c6/0x3b0\n  ? recalc_sigpending+0x15c/0x1e0\n  ? __pfx_kthread+0x10/0x10\n  ret_from_fork+0x36e/0x5a0\n  ? __pfx_ret_from_fork+0x10/0x10\n  ? __switch_to+0x572/0xdd0\n  ? __pfx_kthread+0x10/0x10\n  ret_from_fork_asm+0x1a/0x30\n  </TASK>\n Modules linked in:\n ---[ end trace 0000000000000000 ]---\n\nDelay the final Login Response instead.  isert_get_rx_pdu() runs from\niscsi_target_rx_thread() after conn->rx_login_comp, completed by\niscsi_post_login_handler() after __transport_register_session(); iscsi-TCP\nand cxgbit already take PDUs from that thread, isert alone does not.  The\nbuffers are still posted first, so the initiator's first command does not\nmeet an empty receive queue and nothing depends on RNR flow control, and\nthe header and payload live in isert_conn, not in the struct iscsi_login\nthat iscsi_target_nego_release() frees first.\n\nOver rxe, 400 login cycles per run, the oops appeared in 10 of 20\nunpatched runs and in none of 20 runs with this patch.  An\ninitiator that never waits is handled by the next patch.\n\nNot tested: iWARP, discovery sessions over iSER, and real HCAs."
    }
  ],
  "lastModified": "2026-09-18T18:17:52.480",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}