CyberSecBulletin
CVE-2022-47942NVD status: Modified

Linux Kernel: Out-of-bounds Write

Published Updated By the CyberSecBulletin desk

CVE-2022-47942 is a high-severity out-of-bounds write vulnerability in Linux Kernel from Linux, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. The record lists versions 5.15.62, 5.18.18, 5.19.2 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 3.9% chance of exploitation within 30 days, which is in the top 9.57% of all scored CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Linux Kernel to 5.15.62 or 5.18.18 or 5.19.2, whichever matches your release line, or a later version.
  2. Read the advisory on cdn.kernel.org for workarounds and exact fixed builds.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux Kernel5.15 up to, but not including, 5.15.62; 5.16 up to, but not including, 5.18.18; 5.19 up to, but not including, 5.19.25.15.62, 5.18.18, 5.19.2

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
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:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.18.8HighNVD
CVSS 3.18.8HighCISA (ADP)

Official description

An issue was discovered in ksmbd in the Linux kernel 5.15 through 5.19 before 5.19.2. There is a heap-based buffer overflow in set_ntacl_dacl, related to use of SMB2_QUERY_INFO_HE after a malformed SMB2_SET_INFO_HE command.

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

The underlying weakness: Out-of-bounds Write

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

How developers prevent this class of flaw

  • Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, many languages that perform their own memory management, such as Java and Perl, are not subject to buffer overflows. Other languages, such as Ada and C#, typically provide overflow protection, but the protection can be disabled by the programmer. Be wary that a language's interface to native code may still be subject to overflows, even if the language itself is theoretically safe.
  • Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Examples include the Safe C String Library (SafeStr) by Messier and Viega, and the Strsafe.h library from Microsoft. These libraries provide safer versions of overflow-prone string-handling functions.
  • Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND discusses canary-based detection in detail.

More Out-of-bounds Write vulnerabilities (CWE-787)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
  3. 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 Write vulnerabilities

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