CyberSecBulletin
CVE-2022-48732NVD status: Modified

Linux: Off-by-one Error

Published Updated By the CyberSecBulletin desk

CVE-2022-48732 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 d4b746e60fd8eaa8016e144223abe91158edcdad, 909d3ec1bf9f0ec534bfc081b77c0836fea7b0e2, b2a21669ee98aafc41c6d42ef15af4dab9e6e882 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 d4b746e60fd8eaa8016e144223abe91158edcdad or 909d3ec1bf9f0ec534bfc081b77c0836fea7b0e2 or b2a21669ee98aafc41c6d42ef15af4dab9e6e882 or acc887ba88333f5fec49631f12d8cc7ebd95781c, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 4.9.300 or 4.14.265 or 4.19.228 or 5.4.178, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux4d4e9907ff572bb1d1c0f6913ad6e3d6d4525077 up to, but not including, d4b746e60fd8eaa8016e144223abe91158edcdad; 4d4e9907ff572bb1d1c0f6913ad6e3d6d4525077 up to, but not including, 909d3ec1bf9f0ec534bfc081b77c0836fea7b0e2; 4d4e9907ff572bb1d1c0f6913ad6e3d6d4525077 up to, but not including, b2a21669ee98aafc41c6d42ef15af4dab9e6e882; 4d4e9907ff572bb1d1c0f6913ad6e3d6d4525077 up to, but not including, acc887ba88333f5fec49631f12d8cc7ebd95781c; 4d4e9907ff572bb1d1c0f6913ad6e3d6d4525077 up to, but not including, f071d9fa857582d7bd77f4906691f73d3edeab73; 4d4e9907ff572bb1d1c0f6913ad6e3d6d4525077 up to, but not including, d877e814a62b7de9069aeff8bc1d979dfc996e06; 4d4e9907ff572bb1d1c0f6913ad6e3d6d4525077 up to, but not including, e7c36fa8a1e63b08312162179c78a0c7795ea369; 4d4e9907ff572bb1d1c0f6913ad6e3d6d4525077 up to, but not including, 1b777d4d9e383d2744fc9b3a09af6ec1893c8b1a; and 1 more rangesd4b746e60fd8eaa8016e144223abe91158edcdad, 909d3ec1bf9f0ec534bfc081b77c0836fea7b0e2, b2a21669ee98aafc41c6d42ef15af4dab9e6e882, acc887ba88333f5fec49631f12d8cc7ebd95781c, f071d9fa857582d7bd77f4906691f73d3edeab73, d877e814a62b7de9069aeff8bc1d979dfc996e06
LinuxLinux Kernel4.8 up to, but not including, 4.9.300; 4.10 up to, but not including, 4.14.265; 4.15 up to, but not including, 4.19.228; 4.20 up to, but not including, 5.4.178; 5.5 up to, but not including, 5.10.99; 5.11 up to, but not including, 5.15.22; 5.16 up to, but not including, 5.16.84.9.300, 4.14.265, 4.19.228, 5.4.178, 5.10.99, 5.15.22

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: drm/nouveau: fix off by one in BIOS boundary checking Bounds checking when parsing init scripts embedded in the BIOS reject access to the last byte. This causes driver initialization to fail on Apple eMac's with GeForce 2 MX GPUs, leaving the system with no working console. This is probably only seen on OpenFirmware machines like PowerPC Macs because the BIOS image provided by OF is only the used parts of the ROM, not a power-of-two blocks read from PCI directly so PCs always have empty bytes at the end that are never accessed.

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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