CyberSecBulletin
CVE-2023-52926NVD status: Modified

Linux: Use After Free

Published Updated By the CyberSecBulletin desk

CVE-2023-52926 is a high-severity use after free 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 72060434a14caea20925e492310d6e680e3f9007, 6c27fc6a783c8a77c756dd5461b15e465020d075, a08d195b586a217d76b42062f88f375a3eedda4d 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 72060434a14caea20925e492310d6e680e3f9007 or 6c27fc6a783c8a77c756dd5461b15e465020d075 or a08d195b586a217d76b42062f88f375a3eedda4d, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 6.1.122 or 6.6.68, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux2b188cc1bb857a9d4701ae59aa7768b5124e262e up to, but not including, 72060434a14caea20925e492310d6e680e3f9007; 2b188cc1bb857a9d4701ae59aa7768b5124e262e up to, but not including, 6c27fc6a783c8a77c756dd5461b15e465020d075; 2b188cc1bb857a9d4701ae59aa7768b5124e262e up to, but not including, a08d195b586a217d76b42062f88f375a3eedda4d; 5.172060434a14caea20925e492310d6e680e3f9007, 6c27fc6a783c8a77c756dd5461b15e465020d075, a08d195b586a217d76b42062f88f375a3eedda4d
LinuxLinux Kernel5.1 up to, but not including, 6.1.122; 6.2 up to, but not including, 6.6.686.1.122, 6.6.68

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 CISA (ADP).

Official description

In the Linux kernel, the following vulnerability has been resolved: IORING_OP_READ did not correctly consume the provided buffer list when read i/o returned < 0 (except for -EAGAIN and -EIOCBQUEUED return). This can lead to a potential use-after-free when the completion via io_rw_done runs at separate context.

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

Recent Use After Free vulnerabilities

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