CyberSecBulletin
CVE-2024-27405NVD status: Analyzed

Linux: NULL Pointer Dereference

Published Updated By the CyberSecBulletin desk

CVE-2024-27405 is a high-severity NULL pointer dereference vulnerability in Linux, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions 059285e04ebb273d32323fbad5431c5b94f77e48, a31cf46d108dabce3df80b3e5c07661e24912151, 57ca0e16f393bb21d69734e536e383a3a4c665fd 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 1.3% chance of exploitation within 30 days, higher than 71% of scored CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Linux to 059285e04ebb273d32323fbad5431c5b94f77e48 or a31cf46d108dabce3df80b3e5c07661e24912151 or 57ca0e16f393bb21d69734e536e383a3a4c665fd or 2cb66b62a5d64ccf09b0591ab86fb085fa491fc5, whichever matches your release line, or a later version.
  2. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux9f6ce4240a2bf456402c15c06768059e5973f28c up to, but not including, 059285e04ebb273d32323fbad5431c5b94f77e48; 9f6ce4240a2bf456402c15c06768059e5973f28c up to, but not including, a31cf46d108dabce3df80b3e5c07661e24912151; 9f6ce4240a2bf456402c15c06768059e5973f28c up to, but not including, 57ca0e16f393bb21d69734e536e383a3a4c665fd; 9f6ce4240a2bf456402c15c06768059e5973f28c up to, but not including, 2cb66b62a5d64ccf09b0591ab86fb085fa491fc5; 9f6ce4240a2bf456402c15c06768059e5973f28c up to, but not including, 35b604a37ec70d68b19dafd10bbacf1db505c9ca; 9f6ce4240a2bf456402c15c06768059e5973f28c up to, but not including, 2b7ec68869d50ea998908af43b643bca7e54577e; 9f6ce4240a2bf456402c15c06768059e5973f28c up to, but not including, c7f43900bc723203d7554d299a2ce844054fab8e; 9f6ce4240a2bf456402c15c06768059e5973f28c up to, but not including, 76c51146820c5dac629f21deafab0a7039bc3ccd; and 1 more ranges059285e04ebb273d32323fbad5431c5b94f77e48, a31cf46d108dabce3df80b3e5c07661e24912151, 57ca0e16f393bb21d69734e536e383a3a4c665fd, 2cb66b62a5d64ccf09b0591ab86fb085fa491fc5, 35b604a37ec70d68b19dafd10bbacf1db505c9ca, 2b7ec68869d50ea998908af43b643bca7e54577e
Linuxlinux_kernel9f6ce4240a2b; 2.6.38Not stated
DebianDebian Linux10.0Not stated

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
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
NoneNo data is disclosed.
Integrity
NoneNothing can be modified.
Availability
HighThe component can be taken down completely.

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

Official description

In the Linux kernel, the following vulnerability has been resolved: usb: gadget: ncm: Avoid dropping datagrams of properly parsed NTBs It is observed sometimes when tethering is used over NCM with Windows 11 as host, at some instances, the gadget_giveback has one byte appended at the end of a proper NTB. When the NTB is parsed, unwrap call looks for any leftover bytes in SKB provided by u_ether and if there are any pending bytes, it treats them as a separate NTB and parses it. But in case the second NTB (as per unwrap call) is faulty/corrupt, all the datagrams that were parsed properly in the first NTB and saved in rx_list are dropped. Adding a few custom traces showed the following: [002] d..1 7828.532866: dwc3_gadget_giveback: ep1out: req 000000003868811a length 1025/16384 zsI ==> 0 [002] d..1 7828.532867: ncm_unwrap_ntb: K: ncm_unwrap_ntb toprocess: 1025 [002] d..1 7828.532867: ncm_unwrap_ntb: K: ncm_unwrap_ntb nth: 1751999342 [002] d..1 7828.532868: ncm_unwrap_ntb: K: ncm_unwrap_ntb seq: 0xce67 [002] d..1 7828.532868: ncm_unwrap_ntb: K: ncm_unwrap_ntb blk_len: 0x400 [002] d..1 7828.532868: ncm_unwrap_ntb: K: ncm_unwrap_ntb ndp_len: 0x10 [002] d..1 7828.532869: ncm_unwrap_ntb: K: Parsed NTB with 1 frames In this case, the giveback is of 1025 bytes and block length is 1024. The rest 1 byte (which is 0x00) won't be parsed resulting in drop of all datagrams in rx_list. Same is case with packets of size 2048: [002] d..1 7828.557948: dwc3_gadget_giveback: ep1out: req 0000000011dfd96e length 2049/16384 zsI ==> 0 [002] d..1 7828.557949: ncm_unwrap_ntb: K: ncm_unwrap_ntb nth: 1751999342 [002] d..1 7828.557950: ncm_unwrap_ntb: K: ncm_unwrap_ntb blk_len: 0x800 Lecroy shows one byte coming in extra confirming that the byte is coming in from PC: Transfer 2959 - Bytes Transferred(1025) Timestamp((18.524 843 590) - Transaction 8391 - Data(1025 bytes) Timestamp(18.524 843 590) --- Packet 4063861 Data(1024 bytes) Duration(2.117us) Idle(14.700ns) Timestamp(18.524 843 590) --- Packet 4063863 Data(1 byte) Duration(66.160ns) Time(282.000ns) Timestamp(18.524 845 722) According to Windows driver, no ZLP is needed if wBlockLength is non-zero, because the non-zero wBlockLength has already told the function side the size of transfer to be expected. However, there are in-market NCM devices that rely on ZLP as long as the wBlockLength is multiple of wMaxPacketSize. To deal with such devices, it pads an extra 0 at end so the transfer is no longer multiple of wMaxPacketSize.

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: yes, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Third-party and government advisories

Recent NULL Pointer Dereference vulnerabilities

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