CyberSecBulletin
CVE-2022-49478NVD status: Modified

Linux: Improper Validation of Array Index

Published Updated By the CyberSecBulletin desk

CVE-2022-49478 is a high-severity improper validation of array index 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 4351bfe36aba9fa7dc9d68d498d25d41a0f45e67, 2e004fe914b243db41fa96f9e583385f360ea58e, a3660e06675bccec4bf149c7229ea1d491ba10d7 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 0.29% 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 4351bfe36aba9fa7dc9d68d498d25d41a0f45e67 or 2e004fe914b243db41fa96f9e583385f360ea58e or a3660e06675bccec4bf149c7229ea1d491ba10d7 or 1310fc3538dcc375a2f46ef0a438512c2ca32827, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 4.9.318 or 4.14.283 or 4.19.247 or 5.4.198, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinuxd855497edbfbf9e19a17f4a1154bca69cb4bd9ba up to, but not including, 4351bfe36aba9fa7dc9d68d498d25d41a0f45e67; d855497edbfbf9e19a17f4a1154bca69cb4bd9ba up to, but not including, 2e004fe914b243db41fa96f9e583385f360ea58e; d855497edbfbf9e19a17f4a1154bca69cb4bd9ba up to, but not including, a3660e06675bccec4bf149c7229ea1d491ba10d7; d855497edbfbf9e19a17f4a1154bca69cb4bd9ba up to, but not including, 1310fc3538dcc375a2f46ef0a438512c2ca32827; d855497edbfbf9e19a17f4a1154bca69cb4bd9ba up to, but not including, a3304766d9384886e6d3092c776273526947a2e9; d855497edbfbf9e19a17f4a1154bca69cb4bd9ba up to, but not including, 3309c2c574e13b21b44729f5bdbf21f60189b79a; d855497edbfbf9e19a17f4a1154bca69cb4bd9ba up to, but not including, f99a8b1ec0eddc2931aeaa4f490277a15b39f511; d855497edbfbf9e19a17f4a1154bca69cb4bd9ba up to, but not including, 24e807541e4a9263ed928e6ae3498de3ad43bd1e; and 2 more ranges4351bfe36aba9fa7dc9d68d498d25d41a0f45e67, 2e004fe914b243db41fa96f9e583385f360ea58e, a3660e06675bccec4bf149c7229ea1d491ba10d7, 1310fc3538dcc375a2f46ef0a438512c2ca32827, a3304766d9384886e6d3092c776273526947a2e9, 3309c2c574e13b21b44729f5bdbf21f60189b79a
LinuxLinux Kernel2.6.18 up to, but not including, 4.9.318; 4.10 up to, but not including, 4.14.283; 4.15 up to, but not including, 4.19.247; 4.20 up to, but not including, 5.4.198; 5.5 up to, but not including, 5.10.121; 5.11 up to, but not including, 5.15.46; 5.16 up to, but not including, 5.17.14; 5.18 up to, but not including, 5.18.34.9.318, 4.14.283, 4.19.247, 5.4.198, 5.10.121, 5.15.46

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 3.17.8HighNVD
CVSS 3.17.8HighCISA (ADP)

Official description

In the Linux kernel, the following vulnerability has been resolved: media: pvrusb2: fix array-index-out-of-bounds in pvr2_i2c_core_init Syzbot reported that -1 is used as array index. The problem was in missing validation check. hdw->unit_number is initialized with -1 and then if init table walk fails this value remains unchanged. Since code blindly uses this member for array indexing adding sanity check is the easiest fix for that. hdw->workpoll initialization moved upper to prevent warning in __flush_work.

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

The underlying weakness: Improper Validation of Array Index

The product uses untrusted input when calculating or using an array index, but the product does not validate or incorrectly validates the index to ensure the index references a valid position within the array.

How developers prevent this class of flaw

  • Use an input validation framework such as Struts or the OWASP ESAPI Validation API. Note that using a framework does not automatically address all input validation problems; be mindful of weaknesses that could arise from misusing the framework itself (CWE-1173).
  • Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, Ada allows the programmer to constrain the values of a variable and languages such as Java and Ruby will allow the programmer to handle exceptions when an out-of-bounds index is accessed.
  • Use a CPU and operating system that offers Data Execution Protection (using hardware NX or XD bits) or the equivalent techniques that simulate this feature in software, such as PaX. These techniques ensure that any instruction executed is exclusively at a memory address that is part of the code segment. For more information on these techniques see D3-PSEP (Process Segment Execution Prevention) from D3FEND.

More Improper Validation of Array Index vulnerabilities (CWE-129)

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

Recent Improper Validation of Array Index vulnerabilities

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