CyberSecBulletin
CVE-2022-48672NVD status: Modified

Linux: Off-by-one Error

Published Updated By the CyberSecBulletin desk

CVE-2022-48672 is a high-severity off-by-one error 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 cbdda20ce363356698835185801a58a28f644853, 2566706ac6393386a4e7c4ce23fe17f4c98d9aa0, e0e88c25f88b9805572263c9ed20f1d88742feaf 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 0.25% 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 cbdda20ce363356698835185801a58a28f644853 or 2566706ac6393386a4e7c4ce23fe17f4c98d9aa0 or e0e88c25f88b9805572263c9ed20f1d88742feaf or ee4369260e77821602102dcc7d792de39a56365c, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 4.14.295 or 4.19.260 or 5.4.215 or 5.10.145, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux78c44d910d3e5f96dc6b3695fc1e4efd7c46a455 up to, but not including, cbdda20ce363356698835185801a58a28f644853; 78c44d910d3e5f96dc6b3695fc1e4efd7c46a455 up to, but not including, 2566706ac6393386a4e7c4ce23fe17f4c98d9aa0; 78c44d910d3e5f96dc6b3695fc1e4efd7c46a455 up to, but not including, e0e88c25f88b9805572263c9ed20f1d88742feaf; 78c44d910d3e5f96dc6b3695fc1e4efd7c46a455 up to, but not including, ee4369260e77821602102dcc7d792de39a56365c; 78c44d910d3e5f96dc6b3695fc1e4efd7c46a455 up to, but not including, ba6b9f7cc1108bad6e2c53b1d6e0156379188db7; 78c44d910d3e5f96dc6b3695fc1e4efd7c46a455 up to, but not including, 2133f451311671c7c42b5640d2b999326b39aa0e; 78c44d910d3e5f96dc6b3695fc1e4efd7c46a455 up to, but not including, 2f945a792f67815abca26fa8a5e863ccf3fa1181; 4.7cbdda20ce363356698835185801a58a28f644853, 2566706ac6393386a4e7c4ce23fe17f4c98d9aa0, e0e88c25f88b9805572263c9ed20f1d88742feaf, ee4369260e77821602102dcc7d792de39a56365c, ba6b9f7cc1108bad6e2c53b1d6e0156379188db7, 2133f451311671c7c42b5640d2b999326b39aa0e
LinuxLinux Kernel4.7 up to, but not including, 4.14.295; 4.15 up to, but not including, 4.19.260; 4.20 up to, but not including, 5.4.215; 5.5 up to, but not including, 5.10.145; 5.11 up to, but not including, 5.15.70; 5.16 up to, but not including, 5.19.114.14.295, 4.19.260, 5.4.215, 5.10.145, 5.15.70, 5.19.11

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.

Official description

In the Linux kernel, the following vulnerability has been resolved: of: fdt: fix off-by-one error in unflatten_dt_nodes() Commit 78c44d910d3e ("drivers/of: Fix depth when unflattening devicetree") forgot to fix up the depth check in the loop body in unflatten_dt_nodes() which makes it possible to overflow the nps[] buffer... Found by Linux Verification Center (linuxtesting.org) with the SVACE static analysis tool.

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

The underlying weakness: Off-by-one Error

A product calculates or uses an incorrect maximum or minimum value that is 1 more, or 1 less, than the correct value.

How developers prevent this class of flaw

  • When copying character arrays or using character manipulation methods, the correct size parameter must be used to account for the null terminator that needs to be added at the end of the array. Some examples of functions susceptible to this weakness in C include strcpy(), strncpy(), strcat(), strncat(), printf(), sprintf(), scanf() and sscanf().

More Off-by-one Error vulnerabilities (CWE-193)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Off-by-one Error vulnerabilities

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