CyberSecBulletin
CVE-2022-50131NVD status: Modified

Linux: Out-of-bounds Write

Published Updated By the CyberSecBulletin desk

CVE-2022-50131 is a high-severity out-of-bounds write 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 66c8e816f2f2ca4a61b406503bd10bad1b35f72f, 91443c669d280937968f0aa4edefa741cfe35314, 6402116a7b5ec80fa40fd145a80c813019cd555f 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 0.24% 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 66c8e816f2f2ca4a61b406503bd10bad1b35f72f or 91443c669d280937968f0aa4edefa741cfe35314 or 6402116a7b5ec80fa40fd145a80c813019cd555f or 3c0f8a59f2cc8841ee6653399a77f4f3e6e9a270, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 5.10.137 or 5.15.61 or 5.18.18 or 5.19.2, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux67a95c21463d066060b0f66d65a75d45bb386ffb up to, but not including, 66c8e816f2f2ca4a61b406503bd10bad1b35f72f; 67a95c21463d066060b0f66d65a75d45bb386ffb up to, but not including, 91443c669d280937968f0aa4edefa741cfe35314; 67a95c21463d066060b0f66d65a75d45bb386ffb up to, but not including, 6402116a7b5ec80fa40fd145a80c813019cd555f; 67a95c21463d066060b0f66d65a75d45bb386ffb up to, but not including, 3c0f8a59f2cc8841ee6653399a77f4f3e6e9a270; 67a95c21463d066060b0f66d65a75d45bb386ffb up to, but not including, 62ac2473553a00229e67bdf3cb023b62cf7f5a9a; 5.766c8e816f2f2ca4a61b406503bd10bad1b35f72f, 91443c669d280937968f0aa4edefa741cfe35314, 6402116a7b5ec80fa40fd145a80c813019cd555f, 3c0f8a59f2cc8841ee6653399a77f4f3e6e9a270, 62ac2473553a00229e67bdf3cb023b62cf7f5a9a
LinuxLinux Kernel5.7 up to, but not including, 5.10.137; 5.11 up to, but not including, 5.15.61; 5.16 up to, but not including, 5.18.18; 5.19 up to, but not including, 5.19.25.10.137, 5.15.61, 5.18.18, 5.19.2

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 NVD.

Scoring systemScoreSeverityScored by
CVSS 3.17.8HighCNA
CVSS 3.17.8HighNVD

Official description

In the Linux kernel, the following vulnerability has been resolved: HID: mcp2221: prevent a buffer overflow in mcp_smbus_write() Smatch Warning: drivers/hid/hid-mcp2221.c:388 mcp_smbus_write() error: __memcpy() '&mcp->txbuf[5]' too small (59 vs 255) drivers/hid/hid-mcp2221.c:388 mcp_smbus_write() error: __memcpy() 'buf' too small (34 vs 255) The 'len' variable can take a value between 0-255 as it can come from data->block[0] and it is user data. So add an bound check to prevent a buffer overflow in memcpy().

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. Record last changed materially (score, affected products, status or references).

References

Recent Out-of-bounds Write vulnerabilities

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