What is the CVSS score of CVE-2024-56649?

CVE-2024-56649 has a CVSS 3.1 base score of 5.5 (Medium). CVSS vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H. EPSS exploitation probability: 0.2%.

Is there a patch available for CVE-2024-56649?

Yes, a patch is available for CVE-2024-56649. Update the affected software to the latest version immediately.

Linux Kernel CVE-2024-56649

MEDIUM

NULL Pointer Dereference (CWE-476)

2024-12-27 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Null Pointer Dereference Denial Of Service Linux Linux Kernel

5.5

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

5.5 MEDIUM

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

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Lifecycle Timeline

CVE Published

Dec 27, 2024 - 15:15 nvd

MEDIUM 5.5

DescriptionNVD

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

net: enetc: Do not configure preemptible TCs if SIs do not support

Both ENETC PF and VF drivers share enetc_setup_tc_mqprio() to configure MQPRIO. And enetc_setup_tc_mqprio() calls enetc_change_preemptible_tcs() to configure preemptible TCs. However, only PF is able to configure preemptible TCs. Because only PF has related registers, while VF does not have these registers. So for VF, its hw->port pointer is NULL. Therefore, VF will access an invalid pointer when accessing a non-existent register, which will cause a crash issue. The simplified log is as follows.

root@ls1028ardb:~

tc qdisc add dev eno0vf0 parent root handle 100: \

mqprio num_tc 4 map 0 0 1 1 2 2 3 3 queues 1@0 1@1 1@2 1@3 hw 1 [ 187.290775] Unable to handle kernel paging request at virtual address 0000000000001f00 [ 187.424831] pc : enetc_mm_commit_preemptible_tcs+0x1c4/0x400 [ 187.430518] lr : enetc_mm_commit_preemptible_tcs+0x30c/0x400 [ 187.511140] Call trace: [ 187.513588] enetc_mm_commit_preemptible_tcs+0x1c4/0x400 [ 187.518918] enetc_setup_tc_mqprio+0x180/0x214 [ 187.523374] enetc_vf_setup_tc+0x1c/0x30 [ 187.527306] mqprio_enable_offload+0x144/0x178 [ 187.531766] mqprio_init+0x3ec/0x668 [ 187.535351] qdisc_create+0x15c/0x488 [ 187.539023] tc_modify_qdisc+0x398/0x73c [ 187.542958] rtnetlink_rcv_msg+0x128/0x378 [ 187.547064] netlink_rcv_skb+0x60/0x130 [ 187.550910] rtnetlink_rcv+0x18/0x24 [ 187.554492] netlink_unicast+0x300/0x36c [ 187.558425] netlink_sendmsg+0x1a8/0x420 [ 187.606759] ---[ end trace 0000000000000000 ]---

In addition, some PFs also do not support configuring preemptible TCs, such as eno1 and eno3 on LS1028A. It won't crash like it does for VFs, but we should prevent these PFs from accessing these unimplemented registers.

AnalysisAI

In the Linux kernel, the following vulnerability has been resolved: net: enetc: Do not configure preemptible TCs if SIs do not support Both ENETC PF and VF drivers share enetc_setup_tc_mqprio() to. Rated medium severity (CVSS 5.5), this vulnerability is low attack complexity. This NULL Pointer Dereference vulnerability could allow attackers to crash the application by dereferencing a null pointer.

Technical ContextAI

This vulnerability is classified as NULL Pointer Dereference (CWE-476), which allows attackers to crash the application by dereferencing a null pointer. In the Linux kernel, the following vulnerability has been resolved: net: enetc: Do not configure preemptible TCs if SIs do not support Both ENETC PF and VF drivers share enetc_setup_tc_mqprio() to configure MQPRIO. And enetc_setup_tc_mqprio() calls enetc_change_preemptible_tcs() to configure preemptible TCs. However, only PF is able to configure preemptible TCs. Because only PF has related registers, while VF does not have these registers. So for VF, its hw->port pointer is NULL. Therefore, VF will access an invalid pointer when accessing a non-existent register, which will cause a crash issue. The simplified log is as follows. root@ls1028ardb:~

tc qdisc add dev eno0vf0 parent root handle 100: \ mqprio num_tc 4 map 0 0 1 1 2 2 3 3 queues 1@0 1@1 1@2 1@3 hw 1 [ 187.290775] Unable to handle kernel paging request at virtual address 0000000000001f00 [ 187.424831] pc : enetc_mm_commit_preemptible_tcs+0x1c4/0x400 [ 187.430518] lr : enetc_mm_commit_preemptible_tcs+0x30c/0x400 [ 187.511140] Call trace: [ 187.513588] enetc_mm_commit_preemptible_tcs+0x1c4/0x400 [ 187.518918] enetc_setup_tc_mqprio+0x180/0x214 [ 187.523374] enetc_vf_setup_tc+0x1c/0x30 [ 187.527306] mqprio_enable_offload+0x144/0x178 [ 187.531766] mqprio_init+0x3ec/0x668 [ 187.535351] qdisc_create+0x15c/0x488 [ 187.539023] tc_modify_qdisc+0x398/0x73c [ 187.542958] rtnetlink_rcv_msg+0x128/0x378 [ 187.547064] netlink_rcv_skb+0x60/0x130 [ 187.550910] rtnetlink_rcv+0x18/0x24 [ 187.554492] netlink_unicast+0x300/0x36c [ 187.558425] netlink_sendmsg+0x1a8/0x420 [ 187.606759] ---[ end trace 0000000000000000 ]--- In addition, some PFs also do not support configuring preemptible TCs, such as eno1 and eno3 on LS1028A. It won't crash like it does for VFs, but we should prevent these PFs from accessing these unimplemented registers. Affected products include: Linux Linux Kernel.

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Check pointers before dereferencing. Use static analysis tools to detect null pointer paths.