CyberSecBulletin
CVE-2023-6932NVD status: Modified

Kernel: Use After Free

Published Updated By the CyberSecBulletin desk

CVE-2023-6932 is a high-severity use after free vulnerability in Kernel from Linux, with a CVSS 3.1 base score of 7.0 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 version 6.7 as the first without the flaw, so updating Kernel to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.37% 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 Kernel to 6.7 or a later version.
  2. Update SIMATIC S7-1500 CPU 1518-4 PN/DP MFP to V3.1.5 or a later version.
  3. Update SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP to V3.1.5 or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxKernel2.6.12 up to, but not including, 6.76.7
SiemensRUGGEDCOM RST2428PNot specified in the recordNot stated
SiemensSCALANCE XC-300/XR-300/XC-400/XR-500WG/XR-500 familyNot specified in the recordNot stated
SiemensSCALANCE XCM-/XRM-/XCH-/XRH-300 familyNot specified in the recordNot stated
SiemensSIMATIC S7-1500 CPU 1518-4 PN/DP MFPV3.1.0 up to, but not including, V3.1.5V3.1.5
SiemensSIMATIC S7-1500 CPU 1518F-4 PN/DP MFPV3.1.0 up to, but not including, V3.1.5V3.1.5
SiemensSIMATIC S7-1500 TM MFP - GNU/Linux subsystembefore V1.1; before V1.1.1V1.1, V1.1.1
SiemensSIPLUS S7-1500 CPU 1518-4 PN/DP MFPV3.1.0 up to, but not including, V3.1.5V3.1.5
DebianDebian Linux10.0Not stated
LinuxLinux Kernelbefore 4.14.332; 4.15 up to, but not including, 4.19.301; 4.20 up to, but not including, 5.4.263; 5.5 up to, but not including, 5.10.203; 5.11 up to, but not including, 5.15.142; 5.16 up to, but not including, 6.1.66; 6.2 up to, but not including, 6.6.54.14.332, 4.19.301, 5.4.263, 5.10.203, 5.15.142, 6.1.66

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
HighSuccess depends on conditions outside the attacker's control.
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:H/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 3.17.0HighNVD

Official description

A use-after-free vulnerability in the Linux kernel's ipv4: igmp component can be exploited to achieve local privilege escalation. A race condition can be exploited to cause a timer be mistakenly registered on a RCU read locked object which is freed by another thread. We recommend upgrading past commit e2b706c691905fe78468c361aaabc719d0a496f1.

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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