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Linux Distros Unpatched Vulnerability : CVE-2021-46964

medium Nessus Plugin ID 246479

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Synopsis

The Linux/Unix host has one or more packages installed with a vulnerability that the vendor indicates will not be patched.

Description

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

 - In the Linux kernel, the following vulnerability has been resolved: scsi: qla2xxx: Reserve extra IRQ vectors Commit a6dcfe08487e (scsi: qla2xxx: Limit interrupt vectors to number of CPUs) lowers the number of allocated MSI-X vectors to the number of CPUs. That breaks vector allocation assumptions in qla83xx_iospace_config(), qla24xx_enable_msix() and qla2x00_iospace_config(). Either of the functions computes maximum number of qpairs as: ha->max_qpairs = ha->msix_count - 1 (MB interrupt) - 1 (default response queue) - 1 (ATIO, in dual or pure target mode) max_qpairs is set to zero in case of two CPUs and initiator mode. The number is then used to allocate ha->queue_pair_map inside qla2x00_alloc_queues(). No allocation happens and ha->queue_pair_map is left NULL but the driver thinks there are queue pairs available. qla2xxx_queuecommand() tries to find a qpair in the map and crashes: if (ha->mqenable) { uint32_t tag; uint16_t hwq; struct qla_qpair *qpair = NULL; tag = blk_mq_unique_tag(cmd->request); hwq = blk_mq_unique_tag_to_hwq(tag); qpair = ha->queue_pair_map[hwq]; # <- HERE if (qpair) return qla2xxx_mqueuecommand(host, cmd, qpair); } BUG: kernel NULL pointer dereference, address: 0000000000000000 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops:
 0000 [#1] SMP PTI CPU: 0 PID: 72 Comm: kworker/u4:3 Tainted: G W 5.10.0-rc1+ #25 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.0.0-prebuilt.qemu-project.org 04/01/2014 Workqueue: scsi_wq_7 fc_scsi_scan_rport [scsi_transport_fc] RIP: 0010:qla2xxx_queuecommand+0x16b/0x3f0 [qla2xxx] Call Trace:
 scsi_queue_rq+0x58c/0xa60 blk_mq_dispatch_rq_list+0x2b7/0x6f0 ? __sbitmap_get_word+0x2a/0x80
 __blk_mq_sched_dispatch_requests+0xb8/0x170 blk_mq_sched_dispatch_requests+0x2b/0x50
 __blk_mq_run_hw_queue+0x49/0xb0 __blk_mq_delay_run_hw_queue+0xfb/0x150 blk_mq_sched_insert_request+0xbe/0x110 blk_execute_rq+0x45/0x70 __scsi_execute+0x10e/0x250 scsi_probe_and_add_lun+0x228/0xda0 __scsi_scan_target+0xf4/0x620 ? __pm_runtime_resume+0x4f/0x70 scsi_scan_target+0x100/0x110 fc_scsi_scan_rport+0xa1/0xb0 [scsi_transport_fc] process_one_work+0x1ea/0x3b0 worker_thread+0x28/0x3b0 ? process_one_work+0x3b0/0x3b0 kthread+0x112/0x130 ? kthread_park+0x80/0x80 ret_from_fork+0x22/0x30 The driver should allocate enough vectors to provide every CPU it's own HW queue and still handle reserved (MB, RSP, ATIO) interrupts. The change fixes the crash on dual core VM and prevents unbalanced QP allocation where nr_hw_queues is two less than the number of CPUs. (CVE-2021-46964)

Note that Nessus relies on the presence of the package as reported by the vendor.

Solution

There is no known solution at this time.

See Also

https://ubuntu.com/security/CVE-2021-46964

Plugin Details

Severity: Medium

ID: 246479

File Name: unpatched_CVE_2021_46964.nasl

Version: 1.1

Type: local

Agent: unix

Family: Misc.

Published: 8/9/2025

Updated: 8/9/2025

Supported Sensors: Frictionless Assessment AWS, Frictionless Assessment Azure, Frictionless Assessment Agent, Nessus Agent, Agentless Assessment, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.4

CVSS v2

Risk Factor: Medium

Base Score: 4.9

Temporal Score: 3.6

Vector: CVSS2#AV:L/AC:L/Au:N/C:N/I:N/A:C

CVSS Score Source: CVE-2021-46964

CVSS v3

Risk Factor: Medium

Base Score: 5.5

Temporal Score: 4.8

Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: p-cpe:/a:canonical:ubuntu_linux:linux-lowlatency-hwe-5.19, p-cpe:/a:canonical:ubuntu_linux:linux-oracle-5.0, p-cpe:/a:canonical:ubuntu_linux:linux-oracle-5.13, p-cpe:/a:canonical:ubuntu_linux:linux-lowlatency-hwe-6.2, p-cpe:/a:canonical:ubuntu_linux:linux-gcp-5.11, p-cpe:/a:canonical:ubuntu_linux:linux-hwe, p-cpe:/a:canonical:ubuntu_linux:linux-intel-5.13, cpe:/o:canonical:ubuntu_linux:16.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:linux-oracle-5.3, p-cpe:/a:canonical:ubuntu_linux:linux-hwe-edge, cpe:/o:canonical:ubuntu_linux:22.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:linux-gke-5.15, p-cpe:/a:canonical:ubuntu_linux:linux-oem-5.17, p-cpe:/a:canonical:ubuntu_linux:linux-gcp, p-cpe:/a:canonical:ubuntu_linux:linux-gcp-5.19, p-cpe:/a:canonical:ubuntu_linux:linux-azure-5.19, p-cpe:/a:canonical:ubuntu_linux:linux-riscv-5.11, p-cpe:/a:canonical:ubuntu_linux:linux-riscv, p-cpe:/a:canonical:ubuntu_linux:linux-aws-6.2, cpe:/o:canonical:ubuntu_linux:18.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:linux-gkeop-5.4, p-cpe:/a:canonical:ubuntu_linux:linux-oem, p-cpe:/a:canonical:ubuntu_linux:linux-hwe-6.2, p-cpe:/a:canonical:ubuntu_linux:linux-hwe-5.11, p-cpe:/a:canonical:ubuntu_linux:linux-allwinner-5.19, p-cpe:/a:canonical:ubuntu_linux:linux-aws-5.19, p-cpe:/a:canonical:ubuntu_linux:linux-aws-5.13, p-cpe:/a:canonical:ubuntu_linux:linux-gke, p-cpe:/a:canonical:ubuntu_linux:linux-riscv-5.8, p-cpe:/a:canonical:ubuntu_linux:linux-starfive-5.19, p-cpe:/a:canonical:ubuntu_linux:linux-gcp-5.3, p-cpe:/a:canonical:ubuntu_linux:linux-azure, p-cpe:/a:canonical:ubuntu_linux:linux-aws-5.11, p-cpe:/a:canonical:ubuntu_linux:linux-aws-5.3, p-cpe:/a:canonical:ubuntu_linux:linux-azure-edge, p-cpe:/a:canonical:ubuntu_linux:linux-azure-fde, p-cpe:/a:canonical:ubuntu_linux:linux-oem-6.0, p-cpe:/a:canonical:ubuntu_linux:linux-azure-5.3, p-cpe:/a:canonical:ubuntu_linux:linux-aws-5.8, p-cpe:/a:canonical:ubuntu_linux:linux-nvidia-6.2, p-cpe:/a:canonical:ubuntu_linux:linux-aws-5.0, p-cpe:/a:canonical:ubuntu_linux:linux-oem-5.13, p-cpe:/a:canonical:ubuntu_linux:linux-gcp-6.2, p-cpe:/a:canonical:ubuntu_linux:linux-azure-6.2, p-cpe:/a:canonical:ubuntu_linux:linux-azure-5.11, p-cpe:/a:canonical:ubuntu_linux:linux-oem-5.10, p-cpe:/a:canonical:ubuntu_linux:linux-raspi2, p-cpe:/a:canonical:ubuntu_linux:linux-gke-5.4, p-cpe:/a:canonical:ubuntu_linux:linux-azure-5.8, p-cpe:/a:canonical:ubuntu_linux:linux-hwe-5.19, p-cpe:/a:canonical:ubuntu_linux:linux-gke-4.15, p-cpe:/a:canonical:ubuntu_linux:linux-oracle-5.8, p-cpe:/a:canonical:ubuntu_linux:linux-hwe-5.13, p-cpe:/a:canonical:ubuntu_linux:linux-riscv-5.19, p-cpe:/a:canonical:ubuntu_linux:linux-starfive-6.2, cpe:/o:canonical:ubuntu_linux:20.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:linux-oem-5.14, p-cpe:/a:canonical:ubuntu_linux:linux-azure-fde-5.19, p-cpe:/a:canonical:ubuntu_linux:linux-azure-fde-6.2, p-cpe:/a:canonical:ubuntu_linux:linux-gcp-5.8, p-cpe:/a:canonical:ubuntu_linux:linux-oem-5.6, p-cpe:/a:canonical:ubuntu_linux:linux-hwe-5.8, p-cpe:/a:canonical:ubuntu_linux:linux-gcp-5.13, p-cpe:/a:canonical:ubuntu_linux:linux-oracle-5.11, p-cpe:/a:canonical:ubuntu_linux:linux-oem-6.1, p-cpe:/a:canonical:ubuntu_linux:linux-azure-5.13

Required KB Items: Host/local_checks_enabled, Host/cpu, global_settings/vendor_unpatched, Host/OS/identifier

Exploit Ease: No known exploits are available

Vulnerability Publication Date: 2/27/2024

Reference Information

CVE: CVE-2021-46964