CyberSecBulletin
CVE-2023-3389NVD status: Modified

Kernel: Use After Free

Published Updated By the CyberSecBulletin desk

CVE-2023-3389 is a high-severity use after free vulnerability in Kernel from 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 6.4, 5.10.185 as the first without the flaw, so updating Kernel to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.67% chance of exploitation within 30 days, higher than 53% of scored CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Kernel to 6.4 or 5.10.185, whichever matches your release line, or a later version.
  2. Update SIMATIC S7-1500 TM MFP - GNU/Linux subsystem to V1.1 or a later version.
  3. Update Linux Kernel to 5.10.185 or 6.4, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxKernel5.13 up to, but not including, 6.4; 5.10.162 up to, but not including, 5.10.1856.4, 5.10.185
SiemensSIMATIC S7-1500 TM MFP - GNU/Linux subsystembefore V1.1V1.1
LinuxLinux Kernel5.10.162 up to, but not including, 5.10.185; 5.13 up to, but not including, 6.45.10.185, 6.4
CanonicalUbuntu Linux14.04; 16.04; 18.04; 20.04; 22.04Not stated
DebianDebian Linux10.0; 11.0Not 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 (google.com)
CVSS 3.17.8HighNVD

Official description

A use-after-free vulnerability in the Linux Kernel io_uring subsystem can be exploited to achieve local privilege escalation. Racing a io_uring cancel poll request with a linked timeout can cause a UAF in a hrtimer. We recommend upgrading past commit ef7dfac51d8ed961b742218f526bd589f3900a59 (4716c73b188566865bdd79c3a6709696a224ac04 for 5.10 stable and 0e388fce7aec40992eadee654193cad345d62663 for 5.15 stable).

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

Other vulnerabilities in Kernel

All Kernel vulnerabilities

Recent Use After Free vulnerabilities

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