CyberSecBulletin
CVE-2024-36928NVD status: Modified

Linux: NULL Pointer Dereference

Published Updated By the CyberSecBulletin desk

CVE-2024-36928 is a high-severity NULL pointer dereference vulnerability in Linux, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions 8792b557eb50b986f2496156d486d0c7c85a1524, 10cb803aff3b11fe0bd5f274fc1c231a43e88df6, e28dd1e1bf3ebb52cdb877fb359e8978a51576e3 as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.23% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Linux to 8792b557eb50b986f2496156d486d0c7c85a1524 or 10cb803aff3b11fe0bd5f274fc1c231a43e88df6 or e28dd1e1bf3ebb52cdb877fb359e8978a51576e3 or eae0aec245712c52a3ce9c05575b541a9eef5282, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 5.11 or 5.15.159 or 6.1.91 or 6.6.31, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux64e3affee2881bb22df7ce45dd1f1fd7990e382b up to, but not including, 8792b557eb50b986f2496156d486d0c7c85a1524; 86818409f989fee29c38528ed8fb085655603356 up to, but not including, 10cb803aff3b11fe0bd5f274fc1c231a43e88df6; 1cfef80d4c2b2c599189f36f36320b205d9447d9 up to, but not including, e28dd1e1bf3ebb52cdb877fb359e8978a51576e3; 1cfef80d4c2b2c599189f36f36320b205d9447d9 up to, but not including, eae0aec245712c52a3ce9c05575b541a9eef5282; 1cfef80d4c2b2c599189f36f36320b205d9447d9 up to, but not including, 8a2e4d37afb8500b276e5ee903dee06f50ab0494; c33d5a5c5b2c79326190885040f1643793c67b29; 29d6fe395087710280f8e11d4ae79569c4cb14b7; 5.15.126 up to, but not including, 5.15.159; and 4 more ranges8792b557eb50b986f2496156d486d0c7c85a1524, 10cb803aff3b11fe0bd5f274fc1c231a43e88df6, e28dd1e1bf3ebb52cdb877fb359e8978a51576e3, eae0aec245712c52a3ce9c05575b541a9eef5282, 8a2e4d37afb8500b276e5ee903dee06f50ab0494, 5.15.159
LinuxLinux Kernel5.10.190 up to, but not including, 5.11; 5.15.126 up to, but not including, 5.15.159; 6.1.45 up to, but not including, 6.1.91; 6.4.10 up to, but not including, 6.6.31; 6.7 up to, but not including, 6.8.10; 6.95.11, 5.15.159, 6.1.91, 6.6.31, 6.8.10

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
LocalThe attacker needs local access or must trick a user into running something.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
LowA basic user account is enough.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by CNA.

Scoring systemScoreSeverityScored by
CVSS 3.17.8HighCNA
CVSS 3.14.4MediumCISA (ADP)

Official description

In the Linux kernel, the following vulnerability has been resolved: s390/qeth: Fix kernel panic after setting hsuid Symptom: When the hsuid attribute is set for the first time on an IQD Layer3 device while the corresponding network interface is already UP, the kernel will try to execute a napi function pointer that is NULL. Example: --------------------------------------------------------------------------- [ 2057.572696] illegal operation: 0001 ilc:1 [#1] SMP [ 2057.572702] Modules linked in: af_iucv qeth_l3 zfcp scsi_transport_fc sunrpc nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_ct nf_tables_set nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 ip_set nf_tables libcrc32c nfnetlink ghash_s390 prng xts aes_s390 des_s390 de s_generic sha3_512_s390 sha3_256_s390 sha512_s390 vfio_ccw vfio_mdev mdev vfio_iommu_type1 eadm_sch vfio ext4 mbcache jbd2 qeth_l2 bridge stp llc dasd_eckd_mod qeth dasd_mod qdio ccwgroup pkey zcrypt [ 2057.572739] CPU: 6 PID: 60182 Comm: stress_client Kdump: loaded Not tainted 4.18.0-541.el8.s390x #1 [ 2057.572742] Hardware name: IBM 3931 A01 704 (LPAR) [ 2057.572744] Krnl PSW : 0704f00180000000 0000000000000002 (0x2) [ 2057.572748] R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:3 PM:0 RI:0 EA:3 [ 2057.572751] Krnl GPRS: 0000000000000004 0000000000000000 00000000a3b008d8 0000000000000000 [ 2057.572754] 00000000a3b008d8 cb923a29c779abc5 0000000000000000 00000000814cfd80 [ 2057.572756] 000000000000012c 0000000000000000 00000000a3b008d8 00000000a3b008d8 [ 2057.572758] 00000000bab6d500 00000000814cfd80 0000000091317e46 00000000814cfc68 [ 2057.572762] Krnl Code:#0000000000000000: 0000 illegal >0000000000000002: 0000 illegal 0000000000000004: 0000 illegal 0000000000000006: 0000 illegal 0000000000000008: 0000 illegal 000000000000000a: 0000 illegal 000000000000000c: 0000 illegal 000000000000000e: 0000 illegal [ 2057.572800] Call Trace: [ 2057.572801] ([<00000000ec639700>] 0xec639700) [ 2057.572803] [<00000000913183e2>] net_rx_action+0x2ba/0x398 [ 2057.572809] [<0000000091515f76>] __do_softirq+0x11e/0x3a0 [ 2057.572813] [<0000000090ce160c>] do_softirq_own_stack+0x3c/0x58 [ 2057.572817] ([<0000000090d2cbd6>] do_softirq.part.1+0x56/0x60) [ 2057.572822] [<0000000090d2cc60>] __local_bh_enable_ip+0x80/0x98 [ 2057.572825] [<0000000091314706>] __dev_queue_xmit+0x2be/0xd70 [ 2057.572827] [<000003ff803dd6d6>] afiucv_hs_send+0x24e/0x300 [af_iucv] [ 2057.572830] [<000003ff803dd88a>] iucv_send_ctrl+0x102/0x138 [af_iucv] [ 2057.572833] [<000003ff803de72a>] iucv_sock_connect+0x37a/0x468 [af_iucv] [ 2057.572835] [<00000000912e7e90>] __sys_connect+0xa0/0xd8 [ 2057.572839] [<00000000912e9580>] sys_socketcall+0x228/0x348 [ 2057.572841] [<0000000091514e1a>] system_call+0x2a6/0x2c8 [ 2057.572843] Last Breaking-Event-Address: [ 2057.572844] [<0000000091317e44>] __napi_poll+0x4c/0x1d8 [ 2057.572846] [ 2057.572847] Kernel panic - not syncing: Fatal exception in interrupt ------------------------------------------------------------------------------------------- Analysis: There is one napi structure per out_q: card->qdio.out_qs[i].napi The napi.poll functions are set during qeth_open(). Since commit 1cfef80d4c2b ("s390/qeth: Don't call dev_close/dev_open (DOWN/UP)") qeth_set_offline()/qeth_set_online() no longer call dev_close()/ dev_open(). So if qeth_free_qdio_queues() cleared card->qdio.out_qs[i].napi.poll while the network interface was UP and the card was offline, they are not set again. Reproduction: chzdev -e $devno layer2=0 ip link set dev $network_interface up echo 0 > /sys/bus/ccw ---truncated---

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: NULL Pointer Dereference

The product dereferences a pointer that it expects to be valid but is NULL.

How developers prevent this class of flaw

  • For any pointers that could have been modified or provided from a function that can return NULL, check the pointer for NULL before use. When working with a multithreaded or otherwise asynchronous environment, ensure that proper locking APIs are used to lock before the check, and unlock when it has finished.
  • Select a programming language that is not susceptible to these issues.
  • Check the results of all functions that return a value and verify that the value is non-null before acting upon it.

More NULL Pointer Dereference vulnerabilities (CWE-476)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Recent NULL Pointer Dereference vulnerabilities

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