CyberSecBulletin
CVE-2022-50235NVD status: Modified

Linux: Out-of-bounds Write

Published Updated By the CyberSecBulletin desk

CVE-2022-50235 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 0e57d696f60dee6117a8ace0cac7c5761d375277, dc7f225090c29a5f3b9419b1af32846a201555e7, c2a878095b5c6f04f90553a3c45872f990dab14e 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 0.43% 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 0e57d696f60dee6117a8ace0cac7c5761d375277 or dc7f225090c29a5f3b9419b1af32846a201555e7 or c2a878095b5c6f04f90553a3c45872f990dab14e or f59c74df82f6ac9d2ea4e01aa3ae7c6c4481652d, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 5.15.75 or 5.19.17 or 6.0.3, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux9e291a6a28d32545ed2fd959a8165144d1724df1 up to, but not including, 0e57d696f60dee6117a8ace0cac7c5761d375277; eabc0aab98e5218ceecd82069b0d6fdfff5ee885 up to, but not including, dc7f225090c29a5f3b9419b1af32846a201555e7; 53b1119a6e5028b125f431a0116ba73510d82a72 up to, but not including, c2a878095b5c6f04f90553a3c45872f990dab14e; 53b1119a6e5028b125f431a0116ba73510d82a72 up to, but not including, f59c74df82f6ac9d2ea4e01aa3ae7c6c4481652d; 53b1119a6e5028b125f431a0116ba73510d82a72 up to, but not including, 00b4492686e0497fdb924a9d4c8f6f99377e176c; 5.15.12 up to, but not including, 5.15.75; 5.160e57d696f60dee6117a8ace0cac7c5761d375277, dc7f225090c29a5f3b9419b1af32846a201555e7, c2a878095b5c6f04f90553a3c45872f990dab14e, f59c74df82f6ac9d2ea4e01aa3ae7c6c4481652d, 00b4492686e0497fdb924a9d4c8f6f99377e176c, 5.15.75
LinuxLinux Kernel5.15.12 up to, but not including, 5.15.75; 5.16.1 up to, but not including, 5.19.17; 6.0 up to, but not including, 6.0.3; 5.165.15.75, 5.19.17, 6.0.3

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 3.19.8CriticalCNA
CVSS 3.17.8HighNVD

Official description

In the Linux kernel, the following vulnerability has been resolved: NFSD: Protect against send buffer overflow in NFSv2 READDIR Restore the previous limit on the @count argument to prevent a buffer overflow attack.

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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