CyberSecBulletin
CVE-2023-38431NVD status: Modified

Linux Kernel: Out-of-bounds Read

CVE-2023-38431 is a critical-severity out-of-bounds read vulnerability in Linux Kernel from Linux, with a CVSS 3.1 base score of 9.1 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 5.15.145, 6.1.34, 6.3.8 as the first without the flaw, so updating Linux Kernel to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 1.16% chance of exploitation within 30 days, higher than 68% of scored CVEs.

Patch this week

Critical severity: a successful attack would have severe impact.

What to do

  1. Update Linux Kernel to 5.15.145 or 6.1.34 or 6.3.8, 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
LinuxLinux Kernel5.15 up to, but not including, 5.15.145; 5.16 up to, but not including, 6.1.34; 6.2 up to, but not including, 6.3.85.15.145, 6.1.34, 6.3.8
NetAppSolidfire & Hci Management NodeNot specified in the recordNot stated
NetAppH300sNot specified in the recordNot stated
NetAppH410sNot specified in the recordNot stated
NetAppH500sNot specified in the recordNot stated
NetAppH700sNot specified in the recordNot stated

Version data comes from NVD's product matching. 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
HighAll data handled by the component can be read.
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:H/I:N/A:H. Scored by NVD.

Official description

An issue was discovered in the Linux kernel before 6.3.8. fs/smb/server/connection.c in ksmbd does not validate the relationship between the NetBIOS header's length field and the SMB header sizes, via pdu_size in ksmbd_conn_handler_loop, leading to an out-of-bounds read.

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

The underlying weakness: Out-of-bounds Read

The product reads data past the end, or before the beginning, of the intended buffer.

How developers prevent this class of flaw

  • Use a language that provides appropriate memory abstractions.

More Out-of-bounds Read vulnerabilities (CWE-125)

Timeline

  1. CVE record published.
  2. Record last changed materially (score, affected products, status or references).

References

Third-party and government advisories

Other vulnerabilities in Linux Kernel

All Linux Kernel vulnerabilities

Recent Out-of-bounds Read vulnerabilities

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