CyberSecBulletin
CVE-2023-4211Exploited in the wildNVD status: Analyzed

Arm Mali GPU Kernel Driver Use-After-Free

Published Updated By the CyberSecBulletin desk

CVE-2023-4211 is a medium-severity use after free vulnerability in Midgard GPU Kernel Driver from Arm, with a CVSS 3.1 base score of 5.5 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. Affected Midgard GPU Kernel Driver versions: r12p0 through r32p0. The record does not name a fixed version, so check the vendor advisory. CISA added it to the Known Exploited Vulnerabilities catalogue on October 3, 2023, which means attacks have been observed in the wild.

Patch now

Attackers are already exploiting this vulnerability, according to CISA.

What to do

  1. Update 5th Gen GPU Architecture Kernel Driver to r43p0 or a later version.
  2. CISA's required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
  3. Read the advisory on developer.arm.com for workarounds and exact fixed builds.

Affected products and versions

VendorProductAffected versionsFixed in
ArmMidgard GPU Kernel Driverr12p0 through r32p0Not stated
ArmBifrost GPU Kernel Driverr0p0 through r42p0Not stated
ArmValhall GPU Kernel Driverr19p0 through r42p0Not stated
ArmArm 5th Gen GPU Architecture Kernel Driverr41p0 through r42p0Not stated
Arm5th Gen GPU Architecture Kernel Driverr41p0 up to, but not including, r43p0r43p0

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
NoneNothing can be modified.
Availability
NoneAvailability is not affected.

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.15.5MediumNVD
CVSS 3.15.5MediumCISA (ADP)

Official description

A local non-privileged user can make improper GPU memory processing operations to gain access to already freed memory.

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. Added to CISA's Known Exploited Vulnerabilities catalogue.
  3. Deadline for US federal agencies to remediate, set by CISA.
  4. CISA published its SSVC assessment (exploitation: active, automatable: no, technical impact: total).
  5. Record last changed materially (score, affected products, status or references).

References

Third-party and government advisories

Other vulnerabilities in Midgard GPU Kernel Driver

All Midgard GPU Kernel Driver vulnerabilities

Recent Use After Free vulnerabilities

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