CyberSecBulletin
CVE-2023-53000NVD status: Analyzed

Linux: Improper Validation of Array Index

Published Updated By the CyberSecBulletin desk

CVE-2023-53000 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 3e5082b1c66c7783fbcd79b5b178573230e528ff, 539ca5dcbc91134bbe2c45677811c31d8b030d2d, 41b74e95f297ac360ca7ed6bf200100717cb6c45 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 0.22% 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 3e5082b1c66c7783fbcd79b5b178573230e528ff or 539ca5dcbc91134bbe2c45677811c31d8b030d2d or 41b74e95f297ac360ca7ed6bf200100717cb6c45 or 992e4ff7116a77968039277b5d6aaa535c2f2184, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 5.4.231 or 5.10.166 or 5.15.91 or 6.1.9, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinuxbfa83a9e03cf8d501c6272999843470afecb32ed up to, but not including, 3e5082b1c66c7783fbcd79b5b178573230e528ff; bfa83a9e03cf8d501c6272999843470afecb32ed up to, but not including, 539ca5dcbc91134bbe2c45677811c31d8b030d2d; bfa83a9e03cf8d501c6272999843470afecb32ed up to, but not including, 41b74e95f297ac360ca7ed6bf200100717cb6c45; bfa83a9e03cf8d501c6272999843470afecb32ed up to, but not including, 992e4ff7116a77968039277b5d6aaa535c2f2184; bfa83a9e03cf8d501c6272999843470afecb32ed up to, but not including, f0950402e8c76e7dcb08563f1b4e8000fbc62455; 2.6.153e5082b1c66c7783fbcd79b5b178573230e528ff, 539ca5dcbc91134bbe2c45677811c31d8b030d2d, 41b74e95f297ac360ca7ed6bf200100717cb6c45, 992e4ff7116a77968039277b5d6aaa535c2f2184, f0950402e8c76e7dcb08563f1b4e8000fbc62455
LinuxLinux Kernel2.6.15 up to, but not including, 5.4.231; 5.5 up to, but not including, 5.10.166; 5.11 up to, but not including, 5.15.91; 5.16 up to, but not including, 6.1.9; 6.25.4.231, 5.10.166, 5.15.91, 6.1.9

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: netlink: prevent potential spectre v1 gadgets Most netlink attributes are parsed and validated from __nla_validate_parse() or validate_nla() u16 type = nla_type(nla); if (type == 0 || type > maxtype) { /* error or continue */ } @type is then used as an array index and can be used as a Spectre v1 gadget. array_index_nospec() can be used to prevent leaking content of kernel memory to malicious users. This should take care of vast majority of netlink uses, but an audit is needed to take care of others where validation is not yet centralized in core netlink functions.

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

References

Recent Improper Validation of Array Index vulnerabilities

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