CyberSecBulletin
CVE-2023-3812NVD status: Modified

Red Hat Enterprise Linux 8: Use After Free

Published Updated By the CyberSecBulletin desk

CVE-2023-3812 is a high-severity use after free vulnerability in Red Hat Enterprise Linux 8 from Red Hat, 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. There is no confirmed exploitation so far. EPSS estimates a 0.34% 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 Kernel to 4.19.265 or 5.4.224 or 5.10.154 or 5.15.78, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
Red HatRed Hat Enterprise Linux 8Not specified in the recordNot stated
Red HatRed Hat Enterprise Linux 8.1 Update Services for SAP SolutionsNot specified in the recordNot stated
Red HatRed Hat Enterprise Linux 8.2 Advanced Update SupportNot specified in the recordNot stated
Red HatRed Hat Enterprise Linux 8.2 Telecommunications Update ServiceNot specified in the recordNot stated
Red HatRed Hat Enterprise Linux 8.2 Update Services for SAP SolutionsNot specified in the recordNot stated
Red HatRed Hat Enterprise Linux 8.4 Advanced Mission Critical Update SupportNot specified in the recordNot stated
Red HatRed Hat Enterprise Linux 8.4 Telecommunications Update ServiceNot specified in the recordNot stated
Red HatRed Hat Enterprise Linux 8.4 Update Services for SAP SolutionsNot specified in the recordNot stated
Red HatRed Hat Enterprise Linux 8.6 Extended Update SupportNot specified in the recordNot stated
Red HatRed Hat Enterprise Linux 8.8 Extended Update SupportNot specified in the recordNot stated
Red HatRed Hat Enterprise Linux 9Not specified in the recordNot stated
Red HatRed Hat Enterprise Linux 9.0 Extended Update SupportNot specified in the recordNot stated
Red HatRed Hat Enterprise Linux 9.2 Extended Update SupportNot specified in the recordNot stated
Red HatRed Hat Virtualization 4 for Red Hat Enterprise Linux 8Not specified in the recordNot stated
Red HatRed Hat Enterprise Linux 6Not specified in the recordNot stated
Red HatRed Hat Enterprise Linux 7Not specified in the recordNot stated
LinuxLinux Kernel4.15 up to, but not including, 4.19.265; 4.20 up to, but not including, 5.4.224; 5.5 up to, but not including, 5.10.154; 5.11 up to, but not including, 5.15.78; 5.16 up to, but not including, 6.0.84.19.265, 5.4.224, 5.10.154, 5.15.78, 6.0.8
Red HatEnterprise Linux8.0; 9.0Not stated

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 3.17.8HighCNA (redhat.com)
CVSS 3.17.8HighNVD

Official description

An out-of-bounds memory access flaw was found in the Linux kernel’s TUN/TAP device driver functionality in how a user generates a malicious (too big) networking packet when napi frags is enabled. This flaw allows a local user to crash or potentially escalate their privileges on the system.

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

The underlying weakness: Use After Free

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.

How developers prevent this class of flaw

  • Choose a language that provides automatic memory management.
  • When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.

More Use After Free vulnerabilities (CWE-416)

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

Third-party and government advisories

Other vulnerabilities in Red Hat Enterprise Linux 8

All Red Hat Enterprise Linux 8 vulnerabilities

Recent Use After Free vulnerabilities

Spotted an error? Tell us.